What are “standard” and “non-standard” pressure cookers?- How do “non-standard” pressure cookers affect cooking time?
- Do all pressure cookers actually cook at full 15 psi?
- How does an increase of pressure affect the cooking temperature?
- Is there an electric pressure cooker that cooks at 15 psi?
- How are pressure cooking times affected by high altitude?
- Why do American, European and Asian manufactured pressure cookers all reach different pressures?
- How can I find what pressure my pressure cooker reaches and cooks?
What are “standard” and “non-standard” pressure cookers?
To facilitate the writing of pressure cooker cookbooks and sharing recipes, there is an un-official standard. This standard includes the maximum operating pressure for American Pressure Cookers (15 psi) and the maximum operating pressure for most modern European Cookers (which is about 13 psi for spring-valve type cookers).
Any pressure cooker that does not fall within this range – or used in a high-altitude situation (see below) – is “non-standard.”
There is no international pressure cooker organization that sets a global standard. Pressure cooker UL Rating, which is an American Appliance Testing standard, only states that a domestic pressure cooker “operate at a nominal pressure of 15 psi (103 kPa) or less.” While in Europe the CE rating, the equivalent to the American certification, state that a “simple pressure vessel” can be above .5 bar (7.2 psi) and below 50 bar (720 PSI) . American manufactured pressure cookers adhere to a standard for pressure canners set by USDA in 1917 – 15 psi.
While some European pressure cookers are sold world-wide many of these manufacturers make a separate model specifically for the American market that reaches 15 psi. Some European manufacturers are switching to a single model distributed world-wide that reaches 15 psi. At the writing of this article, American pressure cooker manufacturers only sell their pressure cookers in the United States.
How do “non-standard” pressure cookers affect cooking time?
There is no set rule or formula. Pressure cooking time really depends on the size and density of the food. Most refined grains and quick-cooking vegetables do not need pressure cooking time adjustments, while tough legumes, whole grains and thick roasts will need several minutes more cooking time. In other words, the denser or larger the food, the more time a cooker operating at a lower pressure (thus lower temperature) will need to achieve the same results as a standard cooker.
All recipes and cooking time charts on this website are written to accommodate both “standard” and “non-standard” pressure cookers. When necessary, times are written in a range – standard pressure cookers should use the shorter cooking time (13 minutes) and non-standard pressure cookers the longer (20 minutes).
More Info: Pressure Cooking Times for standard and non-standard pressure cookers
Do all pressure cookers actually reach 15 psi?
This comes down to the difference in measuring systems between the United States (imperial) and the rest of the world (metric). Pressure in the rest of the world is measured in kilopascals (kPa) and bars while the U.S.it is measured with pounds per square inch (psi).
European manufactured pressure cookers are designed to cook at 1 bar or 100 kpa (metric pressure measurements) and that translates to 14.5 psi (this is rounded up to 15 psi) but American manufactured pressure cookers are designed to reach a full 15 psi (see below, for information on electric pressure cookers).
How does an increase of pressure affect the cooking temperature?
The rise in pressure inside the pressure cooker directly correlates to the rise in boiling point – the maximum cooking temperature that can be achieved at a given pressure.
Using the Antoine Equation we also produced more detailed charts.
More Info: Pressure and Boiling Points of Water – The Engineering ToolBox
More Info: Water Vapor Pressure and Boiling Points (Antoine Equation)
How are pressure cooking times affected by “high altitudes”? Isn’t atmospheric pressure already 15 psi?
The pressure cooker adds pressure above the current atmospheric pressure. Since there is a pressure difference in the atmosphere between one altitude and another, the pressure cooker’s pressure will vary accordingly.
At sea level, the atmospheric pressure averages 14.7 psi – add 15 psi of pressure generated by the pressure cooker and the food in the cooker is cooking at 29.7 psi of absolute pressure.
Moving up in the atmosphere, or going to higher altitude, the atmospheric pressure decreases. So in Denver Colorado (about 5,000 feet) the atmospheric pressure averages only 12.2 psi- add 15 psi of pressure generated by the cooker and there the food is cooking at just 27.2 psi of absolute pressure -almost 3 psi less pressure than pressure cooking at sea level!
No matter where you are, a pressure cooker will always add pressure to the current atmospheric pressure.
The same 15 psi pressure cooker will cook 15 psi in San Francisco, California (sea level) but only 12.5 psi in Denver, Colorado (5,000 feet). Now, “standard pressure cooker” has become “non-standard” in Denver. This means that the recipes will need the same timing adjustments used for non-standard pressure cookers (see pie chart, above).
formula to adjust high-altitude pressure cooking times
Increase pressure cooking time by 5% for every 1000 ft above 2000 ft elevation (see table, below). Multiply the recommended cooking time by the number on the table. The result will likely be a decimal value just round that up to the next minute.
[table id=12 /]
More Info: Air Pressure and Altitude Above Sea Level – The Engineering ToolBox
Why do American, European and Asian pressure cookers all reach different pressures?
The transformation from a Renaissance “bone digester” invented by French scientist Denis Papin (in 1689) to pressure canners (1905) and finally to the pressure cooker we know today began in 1926. The Home Exhibition in Paris introduced the first model for home use. The pressure cooker made it out of Europe and into the United States via the 1939 New York Fair where the National Pressure Cooker Company launched the first U.S. model.
Aluminum pressure cookers took off in the U.S. and many companies began producing them. Then, America’s involvement in WWII halted the production of pressure cookers and their factories were dedicated to producing munitions for the overseas war.
Once the war ended, European and American pressure cooker manufacturers began to develop and produce pressure cookers independently from each other. While in America unscrupulous factories made and sold sub-standard pressure cookers – that eventually went on to mar the cooker’s reputation and halt innovation- European manufactures continued to develop, perfect and innovate their designs adding multiple redundant safety mechanisms, selectable pressure levels and more features.
The 90’s started the trickle of European manufactured pressure cookers, and their features into America. It’s also when the patent for the first electric pressure cooker was filed by Chinese scientist, Mr. Yong Guang Wang. The electric pressure cooker was developed independently from stovetop pressure cookers in that they were based on the ever-popular electric rice cookers (hence the resemblance) and are manufactured in a range of pressures – depending on the manufacturer or design team.
Is there an electric pressure cooker that cooks 15 psi?
At the time of the writing of this article, most electric pressure cookers reach 15 psi but they do not cook at 15 psi. As illustrated by the graphic below – electric pressure cookers reach 15 psi briefly during the warming process.
Electric pressure cookers build pressure up to 15 psi but then maintain a lower pressure during the cooking. In the graph below the “operating pressure” is 11.6 even though the cooker reaches 15 psi while it’s building pressure. “Operating Pressure” is the true pressure at which an electric pressure cooker cooks.
More Info: How Electric Pressure Cookers Work – Instant Pot
How can I find out what pressure my pressure cooker reaches?
Most instruction booklets have this information written in them. The number may be written in kPa, bar or PSI (use the table in this page to decode the approximate PSI). There may be several terms used in conjunction with those numbers and they include:
- Operating Pressure – the pressure at which the pressure cooker cooks the food.
- Valve Release Pressure – the pressure at which the main regulating valve releases pressure (2 to 4 psi more than the operating pressure depending on the manufacturer).
- Warping Pressure – the pressure at which the base or components of the pressure cooker deform.
Stove top pressure cookers may also have this information written on the base, and the maximum valve release may be written on or near the valve.
Electric pressure cookers will have the “valve release pressure” written in very small text on the underside of the pressure release valve either on the plastic housing, or the metal part of the valve.
More Info: Free Pressure Cooker Manual Library
More Questions?
Leave a comment below, and we’ll do our best to find the answer.
This is the BEST page I’ve come across that explains the “standard” and “non-standard” pressure levels. :)
According to tests performed by Cooks Illustrated, the pressure cookers which are supposed to reach 15 psi were not actually cooking AT 15 psi, because the water should be boiling at 250 F (121 C) and their temperature readings indicate that only one “15 psi” pressure cooker on test reached 250 F. I can’t help thinking their tests were inaccurate – most likely because they set the stove heat far too low when the pressure level had been reached at the beginning, and then wondered why nothing was cooking properly. What do you think of it Laura:
http://www.cooksillustrated.com/equipment/overview.asp?docid=41600
David, the reviews you point to are flawed in many ways. Cookers which have been judged top cookers by many professionals, including myself, were scored at the bottom while others that I personally consider problematic scored at the top.
I left my thoughts in the egullet forums shortly after their reviews were written, and I hope you don’t mind if I copy and paste them here.. (BTW, I called the WMF 13psi cooker before I reviewed it myself).
“I have used 5 of the 8 cookers listed – 6 if you count the Euro Vitaquick (which appears to be re-disgned for US) and thoroughly reviewed 2 of them.
Can’t say that I agree with America’s Test kitchen’s conclusions. One of the dings is due to apparent user error like “yoyo adjustments” for the Kuhn (user did not find the proper heat setting) and “struggling to maintain pressure” for the Magefesa (the photo of that cooker does not appear to have the valve correctly in place). The “extreme” evaporation from the Kuhn, is due to running the cooker on too-high heat (adjusting a Kuhn is tricky at first – but it’s not impossible ). The article makes a big deal about some cookers not reaching 250F (15psi) but don’t describe how they actually measured the internal temperature – they write the WMF reached 247F which is a bit strange for 13PSI cooker!
Unlike the ATK reviewers, I haven’t had any issues with “bulging cookers”. I absolutely love the “beer belly” on the Fagor Futuro which accommodates larger cuts of meat without having to go to the expense of getting a pressure braiser (though those are REALLY nice, and REALLY wide!) – no scorching, though I haven’t made a crepe in it like ATK testers.
I had the most trouble with their “highly recommended” model – the Fagor Duo. It works great, but it’s tricky to lock the lid shut and to tell when it has really reached pressure – it’s prone to false positives which in turn alerts the cook to turn down the heat too soon.
Unfortunately, I cannot comment on their highly recommended model Vitaquick – I only have their Euro model and could never get it to work properly. I reviewed the big- sister the Vitavit and it broke during the review process (it was great while it lasted – except for the laser-beam three-directional pressure release). On the bright side, the US Vitaquick appears to have substantial changes from the Euro model – and if it’s anything like the US Blue point (their previous US model) then I expect that it performed quite well.”
In addition, we discussed their suspicious selection of electric pressure cookers to review..
“Also, their selection of electric pressure cookers to test was curious. They complained about the non-stick interior, puny size, and spinning inner pot but did not include electrics with stainless steel cooking pots, or the oval 8L electric cooker (which I assume would not spin).”
… to conclude. I think they reviewed pressure cookers like they would review a crock pot, or a can opener – without specific regard to both the origin of the cooker OR the intricacies of basic pressure cooking.
Ciao,
L
Straight away I had the feeling that their reviews were inaccurate and flawed. They should have asked you to test these pressure cookers for them. ;)
I have the Fagor Duo (6 litre capacity), Made in Spain. I have no problems with it at all. I can tell the reviewers were not setting the stove properly. When I use my Fagor pressure cooker, I add the liquid and food, lock the lid, set the pressure dial to 1 or 2 (low or high pressure respectively) and turn the stove up to high. When steam flows from the dial with a strong flow and loud hiss, I turn the heat down; stove setting 2.5 out of 6 – never below 2.5 – and set the timer. Throughout the cooking time it maintains a gentle flow of steam from the dial, never a strong/loud flow of steam – a sign the heat is up too high.
The Fagor IS cooking properly and it never undercooks food. There’s no way it could be cooking below the pressure levels on the dial (8 psi low and 15 psi high) or “not reaching 250 F” (121 C). I can’t fault the Fagor in any way. If the reviewers were having problems then it could only be caused by user error i.e. heat being turned down too low – probably long before a strong flow of steam escapes from the dial; that may explain why they were experiencing problems?
I agree with you David.
Unfortunately, the target for those reviews are people who DO NOT have pressure cookers YET so those readers would not be as quick as you, or I, to see the flaws .
Regardless, America’s Test Kitchen spent lots of $$$ promoting pressure cooking, so I can’t fault them for that!
It will be interesting to see how their marketing tune changes in the coming weeks and months.
Ciao,
L
Great article – I would like to point out that temperature based, sealed, electric pressure cookers would not be affected by altitude.
Dan, although the electric pressure cooker will attempt to reach the same temperature at a higher altitude it cannot compensate for the lower boiling point. The contents are still affected by outside pressure whether the cooker is controlled by a weight, spring or temperature sensor.
In a temperature-controlled electric pressure cooker that “operates” at 11.6 psi at sea level – the heating element will turn ON when the contents reach 115C and OFF when they reach 118C. BUT at 10,000 feet the boiling point for an 11.6psi pressure cooker is lower. The maximum temperature the contents can reach is only about 111C – so, the heating element never gets the signal from the temperature sensor to turn off.
But, don’t worry, electric cookers have a safety trigger that turns off the cooker if it tries to reach pressure unsuccessfully for longer than a per-determined amount of time. Translation: the heating element will not remain on indefinitely.
Ciao,
L
Great article. I do have a question, however. Why would the contents if a pressure cooker be affected by altitude or outside pressure? The interior of the pressure cooker is vacuum sealed (aka airtight) so its pressure is isolated from the air pressure outside the cooker. In essence, it’s identical to the pressurized cabins of an airplane or space craft, which are unaffected by the pressure (or lack thereof, in the case of space) outside. The boiling point would certainly be lower at higher altitudes for a normal unsealed pot, but it shouldn’t matter for an airtight enclosure like a pressure cooker.
I’m pretty sure that the difference is that an airplane is sealed-tight when it is at sea level while a pressure cooker in a high altitude situation seals tight when it is already at high altitude. Also, you’re not trying to boil people in an airplane. ; )
I’ll let Greg, the science expert, give you the conclusive answer, tho.
Ciao,
L
ADDENDUM
I see what you’re saying but shouldn’t a space in a *rigid* enclosure be calculated with absolute pressure and not relative pressure? Since the metal walls of the cooker equalize the outside atmospheric pressure, why is added to the internal pressure? Similarly, the internal pressure of the pressure cooker, i.e. 15 psi, has no effect on the outside pressure. The two discrete spaces are isolated from each other by the walls of the cooker and the silicone seal. Am I missing something?
sam
yes you’re missing something!
you cannot calculate pressure seperately, when you put the lid on your pot whether it’s a pressure cooker or a dutch oven or any other kind of pot the pressure inside is equal to the pressure surrounding it.
the metal walls do not equalise the pressure they simply contain it.
if you look for my reply to jim down this page it may help.
a pressure cooker is designed for use at a stable atmospheric pressure, your question covers changing pressures.
just for fun i checked a few pressures, if you could fit the lid and contain the pressure in your pressure cooker at the peak of mount everest 8,848 meters (253.0 torr) approximately 5psi, then took it to the beach, it would be fun watching you try to open it, as it would now contain a vacuum of around -10 psi :-)
I am a confused person. Is there an electric pressure cooker that achieves an operating pressure of 15.2 psi?
If not, how do I adjust recipes designed to be cooked at 15.2 psi for an electric pressure cooker?
I lost my electric pressure cooker during a move, and want to replace it. I don’t ever want to go back to the stovetop model; I hate the constant adjustments to the heat setting on the burner.
I will be so grateful for your help, as I have gotten no where (except for a bad headache) trying to figure this out myself. Thanks!
There is a manufacturer that claims their electric pressure cooker cooks at 15psi – but if you contact them and ask them what the “operating pressure” is (that is the pressure at which it actually COOKS) they will tell you that it’s about 11 psi.
Ciao,
L
The only electric model I’ve found that *may* cook at 15psi is the Techniques talking 6.5 qt pressure cooker (also branded as Keystone or Shamrock). I base this on 3 things. 1) it has 3 pressure settings: Low, Med (10 psi) and High (15 psi). Of course, as many have pointed out, the company may simply be making an exaggerated claim. 2) The lid is MUCH thicker and heavier, and built like a tank. In fact, my elderly mother can’t lift it. Unlike most lids that simply twist on, this has a sliding lock mechanism with multiple gears (see photo). The heft and lock suggests that the lid was built to withstand higher pressure. As an aside, the Instant Pot website points out that electric models don’t reach 15psi simply because consumers aren’t willing to pay the extra cost to build a stronger lid. Apparently, users think the savings is worth the few extras minutes in cooking. So it’s purely a business decision, not a scientific one. 3) I’ve never had to convert a stovetop pressure cooker recipe and things turn out great. White rice cooks perfectly in 3-4 minutes whereas it takes 8-12 mins in my other models. That suggests that it may actually be cooking at 15psi.
Unfortunately, the Techniques (Keystone or Shamrock) may be discontinued. The good news is that it can be found cheap. For example, I bought a brand new one for $39.99 with free shipping. And it has some unique features rarely found in other models. First, it talks, giving instructions and status reports. I turn this off though because it’s useless and annoying. Much more useful is it’s oval shape. That allows it to more easily accommodate roasts and whole poultry (but also taking up more counter space). Finally, it allows you to program the Keep Warm temperature — something I haven’t seen in any other model except the very expensive Instant Pot Smart. This allows me to use it like a very cheap Sous Vide machine, which often costs $200+. Unfortunately, there is no aerator and it can’t get lower than 140F (beef should be cooked around 130F). But I easily remedy that by leaving a space in the lid, and elevating the beef on a rack. I wish I can get it down to 95F to make yogurt, but I have two other cookers for that, including the Instant Pot.
Regardless, it was a bargain at $39.99 and does cook faster than my other pressure cookers. And yes, I’m talking about cooking time AFTER it reached pressure. Of course, the fact that it uses 1300 watts means a bit faster re-pressurization times during cooking. But observing it shows that re-pressurization time is barely faster than my 1000 watt Instant Pot (I use a watt-meter to show me when the heating element is on). That leads me to conclude that it must be cooking at a higher temperature, hence higher pressure, maybe even at 15 psi. My lab has a thermometer that records the peak/nadir temperature of specimens. Maybe I’ll put the wireless probe into the Technique and see if it actually reaches 250F. And then see if the temperature is sustained. If yes, it’s proof that it is cooking at 15psi. The only question is whether the wireless signal can get through the heavy metal lid and walls. Too bad a wired probe would prevent a vacuum seal.
FYI, this site has the instruction manual (and despite user complaints, yes, you can turn the voice off). And a Google search shows that the Technique/Keystone/Shamrock is still widely available, despite being discontinued. EBay usually has the lowest price.
http://www.hippressurecooking.com/technique-oval-talking-electric-pressure-cooker-manual/
Sam, the only way to confirm their 15psi claim is to measure the temperature. Though, it is TRUE that all electric pressure cookers *briefly* reach 15psi in the heat-up phase it does not mean that they cook at that pressure(and temp) the entire time.
The lid is more sturdy because there is a larger surface area for the pressure to push on it. This is also the case with shorter and wider stove top pressure cookers.
I’m interested in exploring more about why you’re getting uneven results with rice between your electric and stove top pressure cookers – because I recommend the same cooking time for both (except for brown rice)!
Ciao,
L
Hi as a new member to this websiteI wondered if you could answer a couple of questions. I recently purchased a SHEF 3 LITRE pressure cooker (see photo attached ) and am somewhat confused as to the amount of liquid to be used when the minimum is prescribed. With just water my cooker takes 1 litre to the minimum mark and 2 litres to the maximum and 3 litres to the very top. When you say use about a cupful minimum is that after you have put he food in? or should I put the food in and then fill to the minimum mark? I assume that the maximum mark would be used when making soup or stews. Also is it essential to do the pressure test before attempting to cook anything? Regards PJ
Hi and welcome.
Your manual should clearly state how much liquid to use as a minimum. However I just downloaded a copy of it and could not see any information on this important detail with a quick scan. To be on the safe side, two cups of liquid would be a good minimum, though you can probably use a bit less. You can work out how much you need during your pressure test. While this is not essential, it is a very good idea as it will get you used to the way the PC works, and if you measure the liquid you put in , then measure the water again at the end, you will get a good idea of what your minimum needs to be. Put in several cups (measured) of water. Run the PC at high pressure for about an hour. Then allow it to cool and measure how much water is left. Double the difference between the two measurements. And use this as your minimum fluid level for actual cooking. If you like, you can do another 10 minute test and use the minimum you determine here for very short cook times.
The lines you see etched into the sides of the PC are probably maximum fill lines. The higher one is the 2/3 full line and should NEVER BE EXCEEDED. the other one will be the indicator line for foaming foods like pasta, rice and beans. Most recipes will say if you are to use the half fill line for the recipe. This site certainly does. Do not fill above that line if you are making pasta or risotto or hummus for example. You will probably need to halve most recipe quantities to make them suitable for your pot. I regularly make the tuna and pasta recipe from this site in my 2.5L PC, but I only ever use 200g of pasta, and Halve the rest of the ingredients. Prefect for the two of us.
You can cook smaller quantities than the fill lines indicate, but make sure you never use less liquid than you determine in your pressure test. The liquid does not have to be water, but it should not be thickened (ie a roux)
Keep in mind that the gasket is very important. It is also a consumable and will need to be replaced regularly. Also make you you clean both it and the mating surfaces of the lid and pot religiously every time you use the pan.
Take the time to work through Laura’s introduction recipes. They are very worthwhile. Though your fry pan style PC won’t work with the pan in pan style cooking unless you use a very small internal pan.
Oops I missed a couple of points:
As well as cleaning around the gasket, make sure you clean the pressure valve EVERY time you use the PC. If this gets blocked the PC will become dangerous very quickly. There are a couple of extra safeguards but you don’t want to rely on those on a daily basis. They are for emergencies.
The manual says your PC is 90kPa on high pressure. This equates to 13psi. This is a little on the low side, so unless you are right at sealevel, you will want to add a little time to the recipe timings. Most recipe timings are for a 15psi cooker.
To work out when to put the liquid in, simply follow the recipe. For most meat cooking you will braise a little, then add the water. For steaming veg, you will put the water in first, then put a trivet (or plate) in and put the veg on top of that.
Again, for your first few experiences, follow the lessons on this website. They will give you an excellent start on your journey.
You can find the lessons here:
http://www.hippressurecooking.com/learn-to-pressure-cook/
Welcome, PJ!
Greg has done a fine job at explaining everything and directing you to the right information – he even sent me an electronic copy of your pressure cooker manual to read.
Similar cookers can be brought up to pressure with 1/2 (for 3L size) and 1 cup of liquid (for 6L size) – but never having used your particular cooker myself I recommend broader minimum liquid requirements. You can see all of the details, along with my recommendations in the “hip notes” area of your pressure cooker manual page:
http://www.hippressurecooking.com/shef-pressure-cooker-instruction-manual/
Ciao,
L
I have been using my Khun Rikon presure cook for a number of years now and I really love cooking with them. I have a Wolf Gourmet Stove with 4 burners, double oven, grill and flat cooking area. My problem when I am canning or even when I am just making a meal,is that I am unable to maintain the required pressure. I am consistently releasing or it releases on its own its pressure. I have checked the ring and other parts for a problem and have found none. The ring (gasket) appears to be as new as when I purchased the KR Cooker. I read all the comments but there doesn’t seem to be one that pertains to my problem. As you can tell I live in Arizona (at 4,000 feet level) so any suggestion would be helpful. Thanks
Could it be that your wolf stove cannot get the flame low enough? Try moving it to your smallest burner and putting that on the lowest flame and see if it can’t maintain pressure.
If the flame still cannot go low enough, an option is a cast iron flame diffuser similar to this one:
“http://www.amazon.com/gp/product/B0007T25ZC/ref=as_li_ss_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B0007T25ZC&linkCode=as2&tag=vi
Don’t use an aluminum one because it just distributes the heat evenly it doesn’t actually bring the temperature of the flame down.
Ciao,
L
I am unsure if you mean you are unable to keep pressure up, or if the pressure gets too high. Laura has answered the second, but if it is the first, the gasket may still be the problem. For a few dollars, you could simply try a new one. If it resolves the problem, great. If it doesn’t, then you have a spare. Ditto the emergency release valve. Also make sure there there are no dings to the rim of both the post and lid.
Excellent article! My older T-fal has nothing to indicate pressure rating, on the device or in the manual. Purchased in Switzerland 25 years ago. How can I be sure it is for 15 psi?
I know there is a lot to find and discover on this website – one of the things we have is an extensive pressure cooker manual library (under the “pressure cooker info” menu).
As luck would have it, I have the manual for your old pressure cooker. You can view and download it here:
http://www.hippressurecooking.com/t-fal-sensor-pressure-cooker-instruction-manual/
According to the manual, the high pressure is 13psi.
It’s great to hear that this cooker has served you so well, for so long!
Ciao,
L
On my T-FAL of the same vintage, the information is engraved in relief on the underside of the handle (lid piece).
Here is precisely what it says on mine:
BREVET ET MODELE DEPOSES
FRANCE ET AUTRES PAYS
MADE IN FRANCE 90 KPa
It’s hard to read. I had to photograph it first.
There is also “TYPE 3125” marked white ink on a different part of the lid handle underside.
Wow. That is my cooker, but not the manual that came with mine. Thanks so much!
I have a fabulous WMF 4.5 Perfect plus which is great to work with. I get it up to working pressure on the wok burner of the gas hob. I would like to get a smaller pressure cooker to go with this 4.5 one for soups and single portions of rice pudding etc. If I go for a smaller WMF, will I have the same problem as the 4.5 reaching pressure or is there a different way of doing it? If I did have to use the wok burner, I would eventually burn the handles of a smaller pan.
Tim, you should not be bringing your cooker up to pressure on the wok or even quick-boil burner. Generally, these burners are too wide for the pressure cooker base. Although the handles are heat-proof they are NOT flame-proof. Your concern about handles melting on a smaller pressure cooker tells me that the burner you are using to bring the cooker to pressure is too wide. Each time you do this, the handles are super-heated by the flame and the bakelite is being weakened – they will eventually crack or break off. Since WMF has the pressure mechanism integrated at the top of the long handle this is going to be VERY expensive to replace!
When bringing the cooker up to pressure you will need to either turn down the flame until it is small enough to stay under the base of the cooker or use a smaller burner. The flames should not lick the sides of the cooker and definitely be so high or wide as to heat the handles.
Ciao,
L
Laura, just to reassure you, the flames do not lap the side of the pan, the wok burner it is the only one that produces enough Joules to get the pressure valve to close. If I place the pan on any of the other three burners I have on my hob, it will reach simmering temperature for a long time, but will not actually reach a temperature that will allow the pressure valve to close.
That sounds very odd to me i have the widest 5L on the market (I think) at 28cm across the base, and my wok burner will definitely lick the sides of the pot unless I turn it well down. Even my big normal burner needs to be turned down slightly. I know burners vary, and mine are near the top end of the scale for heat output of a domestic cooker, but it sounds to me as though you may have a problem with either your gas supply or the burners themselves If the stove is at all old it may be due for a service.Over time spills will clog the gas jets and reduce gas flow. I find I need to clean the jets on my uncle’s stove about once a year, or the best he can get is a gentle simmer even on his “wok” burner. It is also possible that the PC is not sealing properly
i know I can get my 5L up to pressure on my smallest burner, though I usually use the mid size as it fits there quite well.. I have to use the smallest burner for my 2.5L or I will burn the sides. I do find that the little one is the one that gets most use. I mostly cook for two.
It is only with the WMF pressure cooker that I have to use a higher heat for the pressure valve to reach pressure and close. There are no problems with the gas hob which is cleaned and serviced regularly, it just has a very low Joule output. Getting enough Joules to activate the pressure valve is the problem. It can simmer away for a long time on a lower heat but it is the added output of the larger burner which allows the pressure valve to close. The Demeyere pressure pot is really easy to use and reaches pressure even on the smallest gas burner, but it requires attention to ensure that the pressure is kept whereas once the pressure is reached in the WMF, I leave it on the smallest burner on the lowest setting and it maintains pressure for the duration as required. All seems very unusual.
Fagor duo combi, the short pressure cooker with larger diameter, when used on a Wolf melts the “helper” handle. No flames up the side, apparently just the proximity to the heat source since the taller Fagor pressure cooker with smaller diameter on the same burner is ok. Burning/melting smelll is horrible. Sent an e-mail to Fagor but no response.
Got a response from Fagor saying they will send a replacement helper handle. Asked how to keep the new one from melting/burning. Waiting to hear.
That’s great news, Linda. My understanding is that Wolf ranges are commercial quality so they will likely have burners with higher BTU’s than ones designed for home use. I would use both pressure cookers on the SMALLEST burner available – and make sure one of those is not for “woks” since those usually have more “rings” of flames for a higher heat.
All else failing, I would be careful about managing the intensity of the flame. Making sure that the fire under the pots never gets to the edges (where the heat would lick the sides of the pot).
Ciao,
L
P.S. When I saw photos of America’s Test Kitchen’s test kitchen during their pressure cooker review videos I noticed that they also tested cookers on commercial ranges – which explains some of their review comments about uneven heating and even scorching. It really struck me as unusual, because I expected a show that invents recipes for home cooks to have a line of generic Whirlpool ranges with gas burners and electric coils! Well.. don’t get me started on their pressure cooking cookbook!!! : /
YIKES! I think my pot overheated once. The top long handle is cracked. The bottom plate is slightly warped. But it works well. Will have to do until my Magefesa Rapid 2 pressure indicator valve is replaced.
Laura, thank you so much for the wealth of information you provide. I really appreciate having your knowledge readily available. I am new at this and now I feel like I have a friend I can turn to when I need help. I have an old Fagor Duo 6 quart but I would like to get something smaller as well. Do you think a 2.6 qt braiser type would be big enough for small meals, one person? Thanks again.
Thank you elijan! I write the information that I wish was available just getting started pressure cooking. There is a shortage of factual technical information on pressure cookery – so lots of inaccuracies keep getting passed-on as fact. I hope that my articles, reviews and recipes dispel most of the myths and motivate cooks to move all of their wet cooking to the pressure cooker.
The short answer: Yes, you can cook for one person in a small 2.6 qt pressure pan.
The long answer: I wrote an article for that, too! : )
http://www.hippressurecooking.com/pressure-cooker-capacity-faq-if-it-fits-cook-it/
Have fun poking around and don’t hesitate to ask as many questions as you like.
Ciao,
L
Hello Laura, I hope you can clarify something for me. I have a Tefal Pessure Cooker Secure 5 and on the lid it says 0,8 bar/PS=1,7 bar (which I assumed were the pressure values for low and high). I looked at the most common pressure ranges on this site and I’m not sure where I’m at. I don’t think PS is the same as PSI judging by the values. I’ve noticed so far that cooking takes longer than the recipes call for. The booklet that came with the PC (which I have misplaced) had a time chart for only several types of food and 4-5 recipes. Could you help figuring out the operating pressure of my PC? I have a feeling that I should fallow the non-standard times, but your advice would be most helpful. Thank you!
1.7 bar is around 25 psi! That makes me think it is the maximum pressure the container will take before it explodes. Hopefully the safety features will cut in before that happens.
0.8 is about 11 psi. That puts it in the electric/non standard category. So use the longer time in the recipes on this web site. It also means that recipes from other sources won’t work properly unless you adjust the timing to allow for the lower than standard pressure. This accords with what you have discovered.
Laura has a page of manuals here. Have a look at that and see if you can whistle up a replacement copy of your missing one.
Lots of bedlam and mayhem in while getting ready for and during the trip (still traveling) so other hands have been messing with the site – will take some time to discover the damage put everything back. : )
Ciao,
L
I checked. Your manual is there. For some reason though, I cannot paste the details into the reply box. Laura must have been playing with the security settings again.
Anyway, go to Pressure cooker info (menu bar above). Choose manual library. Follow down the list to T-Fal. Pick “Tefal Secure” from that list. The front page clearly shows “Secure 5”
Also the manual states that Operating pressure is 80 kPa (12 PSI)
and “Maximum Safety Pressure limit” is 170kPa (25 PSI)
Page six of the pdf file.
It is interesting that I rounded the conversion down and they rounded it up.
Thank you very much, Greg. This is very helpful!
Hi Anca, The two numbers you see are operating pressure (0,8bar) and maximum pressure the lid will take before deforming and popping off (1,7 bar). Your pressure cooker operates, or cooks, at 11.6psi. This means it’s a non-standard pressure cooker and you should follow the non-standard pressure cooking times.
Here is a copy of the manual the Greg tried to link to:
http://www.hippressurecooking.com/t-fal-secure-pressure-cooker-instruction-manual/
Come back to let us know if you have any more questions!!
Ciao,
L
Hello, though I’ve had a pressure cooker for a while now I still consider myself new to it. I first bought tefal secure 5 pressure cooker and found that its too big sometimes. I recently bought aluminium combo pressure cooker which is 5.5 l and 2 l. I didn’t know anything about psi and now wonder if I’d better replace my cookers. Apparently tefal cooks at 13 psi max. The new cookers I got don’t state the operating pressure but the manual says the following: “the weight valve operates when the pressure reaches 1 kg/sq cm and emits whistles, which are loud and clear”. This pressure cooker is of Indian made and operates with whistles. So how do I know what is operating pressure of these new cookers I got? And a cooker that is 15 psi, does it cook at this level or does it only reach this level? My head is spinning and I’m confused. We have mostly European and Indian made pressure cookers where I live. I have decided I will replace my tefal with a 15 psi cooker if I find it. But what about the new ones?
Yanachka, Helen has given you some great information and advice. I would only add that to be watchful of the minimum liquid required for your “whistling” pressure cooker – when following recipes on this website. It might be more than one cup since your cooker vents.
Also, here’s some advice on how to tell when your whistling pressure cooker has reached pressure and when to start counting the pressure cooking time:
http://www.hippressurecooking.com/does-your-pressure-cooker-recipe-whistle/
Welcome!
L
1 kg/cm=14.22 PSI according to this article.
http://www.theunitconverter.com/kilogram-force-square-centimeter-to-psi-conversion/
This is pretty close to 15PSI
Pressure cookers are very common in India, so should be good although I wouldn’t cook with tomatoes or acidic ingredients in aluminum.
The tefal looks pretty nice and is 13 PSI is close enough that you would probably not have to add more than a minute if that.
I have an electric pressure cooker which operates at 10.15~11.6 psi and a Fagor Futura that is 15 PSI. I just follow the instructions for 15 PSI for both and the food is always cooked. Sometimes it is a little too cooked even in the 11.2 PSI pressure cooker.
I live at sea level which makes a 2.5 PSI adjustment compared to 5000 feet above sea level.
I also cook pretty small quantities most of the time and both are 6 liter. Only downside is a bigger pot is bigger pot to wash after.
Very good article on size here.
http://www.hippressurecooking.com/pressure-cooker-sizes-and-types/
Most recipes are designed for 6 liter and I have cut many in half, and some in a quarter with no difference.
My understanding is that between 13 and 15 PSI you would maybe have to add a minute or two to longer cooking times, and this is not a significant amount in overall time. Maybe 5% but usually less.
Helen
Thank you Helen, I may have just read a little “too much”. I like my tefal because it “feels good” being stainless steel, but it’s heavy. If there’s space in the dishwasher (there’s always a lack of it lol) I usually put it there and wash the lid by hand, but usually I wash by hand. I like this aluminium because it’s small and light. I cooked tomato sauce in it yesterday and it turned out great, I didn’t feel any weird taste (I’m sensitive to these things). I cooked pasta in the bigger pot and it also turned out great. I so far like the new p.cookers.
Good to hear. I also read a little too much very often.
An aluminum pressure cooker is probably much safer than an aluminum pot because of the much shorter cooking times.
Growing up almost all of my family and acquaintances used cast aluminum pots, many pitted due to heavy use. Nobody seemed to get sick and the food was tasty. Still although I am a little leery, there are far more dangerous things being eaten by millions every day.
I am finding that more and more health concerns are greatly exaggerated.
I never recommend anyone else go against them, but sometimes I do.
Helen
In this article you state “This standard includes the maximum operating pressure for American Pressure Cookers (15 psi) and the maximum operating pressure for most modern European Cookers (which is about 13 psi for spring-valve type cookers).”
I’ve been told that the max for Europe is 150 kPa, which is 21.7 psi?
Yes, there is a difference between standard and maximum. Just because there is a maximum pressure allowed by law in the manufacture of pressure cookers. It does not automatically mean that all manufacturers will create cookers to operate at the maximum allowed pressure. Each manufacturer has both a country-specific history, innovation as well as considerations for the cost of additional materials that work into their decision for the operating pressure of their pressure cookers.
BTW, if you read the answer to the first question in this article, you’ll see that the European maximum limit is actually 50 bar (which is equivalent to 5000kPa).
You might want to go back to the person who told you 150kPa and share this information with them.
Ciao,
L
My pressure cooker is a 12psi and I have no idea how to convert 12psi to 15psi recipes contained in most cookbooks. Certainly I will have to cook for a longer time, but I have no idea how much longer. I am undercooking all my roasts and am very frustrated.
Helen, check out our timing chart. It has the cooking times written in a range (like 15-20 minutes) and you should always use the longer cooking time in the range for your 12 psi cooker. The newer recipes here have cooking time specifically for electric (9-12 psi) or stovetop pressure cookers (13-15psi) – you didn’t mention which one you have but if you have a stovetop that cooks at 12 psi you should follow the cooking time recommended for electric pressure cookers.
Even if you’re following someone else’s recipe, look up the cooking time for the main ingredient here so you can get perfect results. ; )
Welcome to pressure cooking, it will get easier!
Ciao,
L
Welcome Helen,
What Laura said.
But if you want a more general rule of thumb, Have a look at Laura’s altitude tables above
The first one says that a 15psi PC effectively cooks at 12psi at 6,000 ft, The second one says that you need to add 25% to the cooking time if you are cooking at 6,000 ft. If you put the two together and apply to your situation, you need to add a quarter to the time given for 15psi recipes. Assuming you are more or less at sea level that is – less than say 1,000 ft.
Actually, I am inclined to think this is a little excessive. try 20% first and see how it goes. You can always put the lid on and cook some more. You can’t uncook overcooked food.
Another thing to keep in mind is that many of the PC recipe books out there have been written by people not all that familiar with them. And in some cases they clearly haven’t even tested the recipe. I have thrown out several since I learned enough to realise it was them not me. Mind you, sometimes it was me. Sigh.
Wow! What a great site, just what I need! I hope you can help me with a question that recently came up for me. I live in Colorado at around 8000 feet altitude. I have the opportunity to purchase a 6.5qt WMF cooker from a friend who has hardly used it (just not her cup of tea), but I wonder if the 13.8 psi would be enough at this altitude. Would I use the WMF pretty much the same as a Fagor or KR? I know I will have to adjust cook times in any case, and I am fine purchasing a 15psi model new if it makes a significant difference over the WMF. If we’re talking a few minutes, though, I am happy to buy the used one. I want something that will work reliably, last long, and not add too much more to cook time. Do you have any model or usage recommendations? Thanks in advance!
If you’re here, you’ve already seen the “adjusted pressure” chart which shows that what the adjusted pressure inside the pressure cooker will be at your altitude. I know there’s a lot to read here (it can be overwhelming) but take a peek at the review I wrote for WMF Perfect Plus – at the beginning I talk about the pressure difference between WMF and other pressure cookers (Fagor/Kuhn Rikon), how significant it is/isn’t, and how it affects cooking:
http://www.hippressurecooking.com/pressure-cooker-review-wmf-perfect-plus-rating/
So when you use it, remember that you’ll have to nearly double the recommended pressure cooking time – it’s still going to be faster than NOT using a pressure cooker for you!
Ciao,
L
Am I understanding this right?
A 15 PSI pressure cooker would require 35% more time and a 13.5 PSI pressure cooker would require 45-50% more time at 8000 feet? Sometimes I struggle with the concept but I try to understand:(.
The first. Yes. The second, I suspect even more. Probably 55%.
But keep in mind at those altitudes unpressurized vessels will be even worse.
Is it ok to leave an electric pressure cooker unattended?
Yes. I not only leave the house with it on, sometimes I set-it up to cook dinner and have it ready when I get home. : ) Make sure you do this with a recipe you know is no fail (all the hip recipes) as you don’t want to come home to a burned or under-cooked mess!
Ciao,
L
I’m having a hard time understanding why people think that elevation above sea level makes any difference to a pressure cooker–at least one with a weighted gauge. Is ambient air pressure lower at higher elevations? Of course it is. Does water boil at a lower temperature the higher you go? Under ambient conditions, you bet it does.
But does your pressure cooker’s control on its internal pressure depend on external air pressure? Mine does not. Mine uses a weighted gauge that the internal pressure has to push upwards. When internal pressure reaches 15 pounds, for instance, the gauge starts to lift off, thus releasing pressure in excess of 15 pounds. This is therefore not pressure vs. pressure, but pressure vs. gravity. Since gravity, for all practical purposes, is a constant even at the highest terrestrial elevation, the 15 pounds of pressure in my cooker in Denver would be the same 15 pounds of pressure using the same cooker in Death Valley.
Thoughts?
your thinking is wrong headed, i thought the same to begin with.
whenever you close your pot the pressure inside is equal to atmospheric pressure which can be considered zero for this purpose, on heating it takes an additional 15 psi to open the valve/raise the weight.
so whatever the current atmospheric pressure is that 15psi is added to it.
as you say it makes no difference to the weight it has to lift, but it does mean it has a different starting point, closing the pot when the current pressure is 10 psi add 15 psi and you have a total of 25 psi etc, it’s that total pressure that determines the boiling point.
this is why you must add the 15 psi to the current atmospheric pressure.
What you are missing is that it is pressure PLUS pressure that affects temperature. Not pressure Vs pressure.
The boiling point is determined by the TOTAL pressure in the vessel. This is atmospheric plus gauge (PC) pressure. At sea level, this is 30psi. At altititude, this may be 27psi or even 20 depending on altitude. All pressure cookers only talk about the contribution made by the PC. This is (nominally) 15psi. Not the total 30psi that is important.
It is a little known fact that atmospheric conditions will also affect cooking times. Though this will probably only be a practical issue during a cyclone. And you almost certainly won’t be worried about cooking during one of those.
In theory, you could compensate for altitude by changing the weight or spring to alter the pressure in the vessel but I am not aware of any PC that allows for this.
Most who talk about altitude corrections talk as if the altitude affects the PC gauge pressure. It does not. The pressure is still 15psi above ambient. But the EFFECT is the same as if the PC is operating at say 12psi. As the ambient is 3psi lower than expected.
Thanks for responding, Greg.
I agree that we can disregard normal barometric fluctuations most of the time, but your mention of cyclones is interesting.
Are you saying that at sea level (for instance), a pressure cooker would have a starting ambient pressure of 15 psi, plus (let’s say) it is operating at a stable 15 psi. That means an actual interior pressure of 30 psi.
Now let’s imagine meanwhile that a hurricane passes by that lowers the ambient pressure by 5 psi. Everything else remains the same, including the rate of heat input. What happens to the pressure, temperature, or time needed to accomplish our cooking task?
Thanks Greg for jumping in and clearing this up!
Jim, you’re overthinking it. Cyclone or not, if the pressure cooker is operating at a lower pressure the food will take longer to cook. BTW, gravity is reduced as you move further up in the atmosphere but at the heights that are possible for humans to inhabit the difference is not significant enough to impact pressure cooking.
https://www.mansfieldct.org/Schools/MMS/staff/hand/lawsgravaltitude.htm
Ciao,
L
Laura. I think this is a hypothetical. More my territory than yours.
If the PC is already at pressure at normal sea level pressure and a hurricane (cyclone* in my neck of the woods) suddenly lowers atmospheric pressure by 5psi, then first up the contents will boil as the boiling point will suddenly lower by 5°C. This will add extra steam into the PC, momentarily increasing the pressure which will vent. It will quickly stabilize at a lower temperature and total pressure. The gauge pressure returning to what it was before. Because the temperature has lowered, food will take longer to cook. Refer to the charts above for the altered timing. If it was something delicate like a custard or fish, it will probably be ruined.
Note to self… Check how much a typical category 5 cyclone/hurricane/typhoon will realistically lower pressure.
*Yes I know there are some differences, but the effect on air pressure is the same.
From encyclopedia brittanica:
“Typically, atmospheric pressure at the surface of Earth is about 1,000 millibars. At the centre of a tropical cyclone, however, it is typically around 960 millibars, and in a very intense “super typhoon” of the western Pacific it may be as low as 880 millibars. ”
880 mbar is about 12.7 psi. So about a drop of 2.3psi Around the same as 4,000ft altitude.
I don’t think that this drop will significantly affect the cooking time – just as the difference between stovetop and electric (14.5 vs. 11.6 psi) is just a few minutes cooking time. But, realistically, I don’t think these conditions will happen frequently enough and – more realistically you are hunkering down or driving away for cover in this situation instead of making a meal.
Ciao,
L
Hi Laura, can you recommend industrial pressure cooker that can produce 120degress C and 25psi? Thank you!
Marianne, you should be shopping for an “autoclave” – they make different sizes for different uses (dentist, tattoo artist, commercial food production). They even sell them on amazon! To make our life easier, go with an electrically controlled model – if you can afford it!
Ciao,
L
Thanks, Linda! great help…