how to change safety valve of pressure cooker in stock

Pressure cooking is a wonderful way to prepare food that cooks thoroughly and quickly at a high temperature. Some are worried about the dangers of using a pressure cooker, so it is helpful to find out how to check your pressure cooker safety valve for safe operation.

For those worried that a pressure cooker might explode, the safety valve is the design feature that prevents this from happening. If the cooker has a safety valve, you can see it installed on the cooker’s lid.

A pressure cooker is designed to trap the steam inside to increase the pressure. However, too much pressure is not safe. The valve must release pressure if it gets too high.

The blog of pressure cooking today has many recipes that are delicious. There are 25 recipes for pasta so you can try a new one every day for nearly a month.

There is a weight inside many of the safety valves that is lifted by the internal steam pressure when it reaches a certain amount. When the pressure lifts the weight inside the valve, this allows some steam to escape.

Jeffrey Eisner who says “he is a nice Jewish boy from Long Island.” He started with pressure cooking by making a simple mac and cheese dish with a recipe that he shared on YouTube. The video was an immediate success and led to his making new recipes for pressure cooking.

In a sealed cooker, as the pressure builds up, the boiling point of water rises. This phenomenon is the cause of the increased heat that cooks the food more thoroughly and faster.

The science that explains this is fascinating. The normal boiling point of water under standard atmospheric pressure of 15 pounds per square inch (psi) is 212°F (100°C). In a pressure cooker, the atmospheric pressure doubles from 15 psi to 30 psi. This added pressure raises the boiling point of water from 212°F (100°C) to 250°F (121°C).

If you see steam escaping from the safely valve do not worry. The steam escaping from the safety valve is its normal function, which means the valve is working properly.

If the internal pressure within the cooker gets high enough, this lifts a weight in the safety valve that allows steam to escape. The escaping vapor lowers the pressure. You can hear the steam escaping, making a whistling sound, or rattling the valve.

The first pressure cooking devices were used in the 17th century. They were useful to remove fat and collagen from bones so that the bones could then be ground down to make a pure bone meal.

The inventor of the device, Denis Papin, called it a “steam digester” or “bone digester.” His invention was the precursor to both pressure cookers and the steam engine. Surprisingly, the early designs did not have any safety features, and this caused some of the first ones to explode while being used.

The legacy of those early pressure-cooking devices may be why some still fear this problem even today. Papin, to his credit, came up with a design improvement that is what we call a safety valve to avoid the dangers of these explosions.

By the 1930s, the modern pressure cooker design became useful in a home kitchen. The Flex-Seal Speed Cooker, invented by Alfred Vischer, came out in 1938.

These home cookers became even more popular in 1939 with the release of the design by the National Pressure Cooker Company (now called National Presto Industries), which is still manufacturing these cookers today.

The first-generation cookers had a safety valve that worked with a weight. When the internal pressure rises high enough to lift the weight, some steam escapes, and the valve makes a distinctive rattling sound.

Second-generation cookers use a spring-loaded valve that makes less noise and is adjustable for pressure sensitivity by using a dial, which is on the cooker.

Third-generation models are the most recent versions. They use an electric heating source that is regulated by the internal pressure. These devices do not need a safety valve because the heat source automatically shuts off before the pressure gets too high.

Suppose you are thinking about getting a new cooker. In that case, there is another device that you might consider called a food dehydrator, which I describe in the article entitled, “How Much Electricity Does a Dehydrator Use?” here.

For the styles of cookers with a safety valve, it may not be obvious when the valve is not working if it is blocked. You may notice the lack of steam while the cooker is heated. The valve could rarely be blocked, but if not cleaned properly, it is possible.

Alternatively, the valve may be broken, missing, or the pot may not seal properly. These problems might allow too much steam to escape. This leakage may cause the cooker not to heat up properly and not allow the internal pressure to build up to the proper level.

One of the signs of a problem with a lack of pressure is that the food takes much longer to cook than you normally expect when using a cooker of this type.

One tip in the video is not to open the cooker after finishing cooking and take the lid to run it under cold water. This sudden temperature change can make the safety valve work less well and may cause the need to change the valve more frequently.

If you use a cooker that needs a valve to work properly and the valve is broken or missing, you can replace it with a new valve. Be sure to get the manufacturer’s specifications to ensure you use the correct replacement part.

Some of these problems include the ventilation knob being open or not enough liquid is in the cooker (requires at least one cup). Another cause is the sealing ring is missing, damaged, covered with food particles, or not in the proper position.

The video narrator shows how she cleans her float valve for her instant pot that she uses as a cooker. If you use too little liquid or too much, the cooker may not pressurize.

For the type with screws, hold the valve from the bottom of the lid with the pliers and use the screwdriver to remove the screws from the top to remove the broken part. Replace it with the new one and tighten the screws that hold it in place by holding it with the pliers from the bottom of the lid again and tightening the screws from the top.

For the type with a nut, use the wrench to loosen it for removal and perhaps a socket when you put on the new valve to tighten it with enough torque to hold it securely in the proper position.

Modern pressure cookers that are in good repair are quite safe. The one caution to remember is not to overfill the cooker so that the food might block the safety valve. This overfilling with food would be very difficult to do and not something to worry about for normal use.

Be careful where you keep your cooker on the countertop because it is important to know how hot a stovetop can get. Even when turned off, a stovetop may still be very hot, which I discuss in this article.

Now you know everything you need to know about a pressure cooker safety valve. You know what they do, how they work, and how to replace one if it needs repair. Enjoy your pressure-cooking recipes without worrying about the safety valve.

If having a safety valve on your cooker still bothers you, consider buying an electric cooker without a valve that instead has a built-in safety feature that automatically shuts off power if the pressure gets too high.

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The chemical reactions going on in a flame are extremely complex radical reactions and hard to follow. Many variables hard to control like oxygen to fuel ratio, temp, turbulences etc.. Analytics are a nightmare.

Soot is basically graphite and some smaller polyaromatic hydrocarbon species magically generated from propane, an alkane. Don’t ask me how, LOL (impossible to explain in text without drawings to say the least.).

I do believe that these higher hydrocarbons are one main part of the stench. So as long as you can make the flam burn clean (e.g. low flame) you will be off a lot better.

Now the sulfur comes into play: sulfur compounds with low valent sulfur (only carbon or hydrogen attached to the sulfur) are know to be the most horrible and reeking substances of them all, chemists hate to work with them. Their odor threshold is extremely low. So minute quantities of these are smellable and the amount in gas is measure in ppm or ppb. Normally ethyl mercaptan or tetrahydrothiophene are used as odorizers, but it don’t really matter what you use. Sulfur dioxide is many orders of magnitude less smelly. You can smell it when lighting a match but this is a bazillion times more than the SO2 you get out of burning gas with an odorizer.

Now let’s consider incomplete combustion with the thiols on board: this might also lead to sulfur containing higher hydrocarbons that cause some awful smell and taste.

To sum it up: we certainly have some freaking aromatic hydrocarbons which would cause a typical fuel taste plus maybe some similar compounds with the added sulfur kick in em.

Both would be very lipophilic and love to go into anything containing fat but be a lot more reluctant to condense onto starch. So this is pretty straight forward.

Regarding the sulfur you could do some controls to see if the original thiol is causing the off taste. You could blow the not ignited torch into some neutral veggie oil or onto a fat impregnated paper towel, and see what you can pick up in smell and taste. If this is what you sensed earlier it is clear you are correct and it is said sulfur compound. If it has a different taste, we are back to speculation.

I know you usually take a lot of care to control all variables but nevertheless let me ask you the following to challenge your observation that low and high thiol fuels behave differently:

If they were the same I´ll go with your hypothesis, otherwise I´d say it is the different flame characteristics that cause different amounts of soot and higher hydrocarbons to form.

If I was U, I’d use my considerable engineering skill pair with my lack a fear to try and design my own flame thrower based on something that burns notoriously clean like alcohol. I proposed abusing a MSR Whisperlite or some similar camping cooker initially designed for white fuel as a possible starting point for this ghetto flame thrower in some earlier post.

P.S.: on the acid issue for your stock: citric might be good to stop Maillard rx. And to keep white stocks white, but it will be a little to weak to speed up the hydrolysis of you meat considerably. For this I have a new proposal: how bout phosphoric acid: it’s not reacting with stainless (it is used to inertize steel), it is non toxic (think Coke) not volatile (good for the aluminum autoclave) and pretty strong……

There’s more than one way to open a pressure cooker and each way has its own effect on what’s inside.  What might work for a stovetop pressure cooker, might not work for an electric pressure cooker. We’re sharing the “how’s” for each of these pressure cooker opening methods to get beginners started and the “why’s” for expert cooks to sharpen their skills.

10-Minute NaturalSlowCount 10 minutes, and then release remaining pressure by opening the valve. If the pressure dissipates sooner than 10 minutes do not remove lid until time is up.1010

Using the wrong opening method can give you limp veggies, bean mush or rock-hard dry meats – here are a three principles that you must know to choose the right opening method for your pressure cooker recipe:

When the pressure cooker is both building and releasing pressure, the temperature inside is near or above the boiling point, which means the food is actually cooking during this time, too.  This is generally fine for meats, legumes and desserts.  It is not fine for vegetables that you may want to have more al dente as they continue to cook during this time-  choose the fastest release method  for veggies while more robust foods will benefit from a longer opening method.

The speed at which pressure is released is directly related to how much movement is inside the pressure cooker – more speed gives the food more movement. When pressure is released, the equilibrium that suppressed the bubbles of the boil during pressure cooking is broken and they begin breaking to the surface again. A fast release will violently release these bubbles, forcefully flinging bits of food and foam onto the underside of the lid and safety valves, while slow opening method,  such as Natural release, delicately allows the bubbles to rise into a  slow lazy simmer.  For foods which you intend to keep whole (like beans) or clear (like stock) use the slowest opening method to get the least amount of movement.

The difference in temperature between the food that comes out of the pressure cooker and the environment can affect the speed of evaporation. The faster opening methods will yield the hottest food with an accelerated evaporation of the food’s cooking liquids and juices. While the slowest opening method will have given the food a chance to cool down and the liquids will evaporate at the speed of conventional boiling.  So for foods which you intend to keep juicy (like roasts) use a slow opening method; while, foods which need reduction after pressure cooking (like a sauce), use a fast opening method.

If this is starting to sound complicated, don’t worry: all of the recipes on this website (and my cookbook) already call for the appropriate opening method. Let’s get into the “how’s”.

This list includes an opening method I came up with (Slow Normal) and another that has been unofficially around for many years (10-minute Natural) –  they add more options to your pressure cookery.  We start the list with the fastest opening method and conclude with the slowest. Further down, there’s an opening method we no longer recommend and one that used to be OK for older cookers but should not be used on modern stainless steel pressure cookers.

Sometimes this method is called Quick, Manual and, confusingly, Automatic. This is a fast opening method that can take 2 to 3 minutes.  Normal pressure release means that the cook should use the valve, or pressure releasing mechanism particular to their cooker  (such as a button to push, a lever to twist, or a slide to pull), to release pressure.  For thick recipes such as a chili or a risotto the still unopened pressure cooker should be given a few small jolts to release any super-heated seam pockets in the food after pressure is released.  This release method is used for quick-cooking foods and vegetables. It should not be used for most legume, rice and fruit-based recipes. It can be used for meat stew-type recipes (where the meat is completely covered with liquid) – but not ones where tossing the other ingredients around would mush them.

Weighted or jiggle-type pressure cookers may not have this kind of release – we recommend either using Natural Release (see below) or simply using a fork tines to gently lift the weight and release pressure.

This is a relatively fast opening method and can take from 5 to 6 minutes depending on the pressure cooker type (the element in electrics still retains heat after turning off) and fill level (more food will retain more heat).  Similar to Normal release, this method releases pressure using the cooker’s valve,  or the pressure releasing mechanism, but pressure should be released very slowly.  If the valve only allows for pressure to release full-throttle, the cook should release it in very short bursts- if anything other than steam sprays out of the valve (like foam), the valve should be closed for 10 seconds before the next slow release or short burst. The Slow Normal release is for occasions where it’s just not practical or convenient to wait for the full Natural or 10-Minute Natural release or for tricky foods (grains, legumes and fruits).

This is a slow and somewhat delicate pressure release, and as the name suggests, takes only 10 minutes – a little more if there is still pressure in the cooker that needs to be released (usually with electrics).  The 10-Minute Natural release allows for pressure to release naturally for 10 minutes and then, if there is any remaining pressure,  it is released using the Slow Normal method.  Conversely, if the pressure in the cooker goes down beforethe10 minutes are up, the lid must remain closed and the cooker undisturbed for the full 10 minutes. This method is recommended for grains which continue to cook in the residual steam locked inside the cooker without any additional heat.  The 10-Minute Natural can also be used in place of Natural Release.

This is the slowest and most delicate pressure release method, it can take anywhere from  10 to 30 minutes depending on the pressure cooker type (electrics take longer due to their thermos-like construction) and fill level (fuller pressure cookers will take longer).  The Natural release lets pressure release slowly from the cooker once the heat (or cooking program) is turned off .  It’s most recommended  opening for tricky foods that tend to foam or expand  like grains, legumes and fruits to prevent the food or its foam from spraying out of the valve;  foods that need to cool down slowly  such as braised and steamed meats and desserts to prevent their moisture from evaporating too quickly;  and,  stocks to keep the food from tossing the ingredients around in a way that would cloud it.

Some opening methods can fall out of fashion because they are either too problematic or the materials used to make the cookers (such as 100% aluminum) are no longer popular.

Using the right opening method can help a recipe end on the right note but it’s also a question of safety.  The wrong opening method could clog the safety valves or even damage the pressure cooker.