Tier 4 · Wet Heat
TO PRESSURE COOK
Cooking in a sealed vessel where trapped steam raises the pressure, and with it the temperature at which water boils.
Why it works
Water boils at 100°C because that is where its vapour pressure matches the air above it. Seal the vessel and the escaping steam raises that pressure — at roughly one atmosphere above ambient, water boils at about 121°C instead. That twenty-one degree difference is large in chemical terms: reaction rates roughly double for every ten degrees, so collagen conversion and starch gelatinisation run several times faster, and dried beans that would take two hours take twenty-five minutes. The trade is that browning is impossible inside — the environment is saturated with water, so no surface can exceed 100°C and Maillard reactions cannot proceed. Everything that needs browning has to be seared before sealing. Nothing reduces either, since no steam escapes, so recipes use markedly less liquid than their conventional equivalents.
How to tell
- Timing starts when full pressure is reached, not when the lid goes on — the come-up can be ten minutes on a full pot.
- A steady quiet hiss or a gently rocking weight means it is holding pressure; loud continuous jetting means the heat is too high.
- Natural release takes ten to twenty minutes and continues cooking; quick release stops it immediately, and the choice is part of the recipe.
- The lid should not open at all until the pressure has genuinely dropped.
When it goes wrong
- Food is overcooked to mush.
- Conventional timings used, or natural release on something already done. Cooking continues through the release, and at these temperatures a few minutes is a lot.
- Watery, thin sauce.
- Conventional liquid quantities. Nothing evaporates in a sealed vessel, so a recipe adapted from a stovetop stew ends up flooded.
- It never came to pressure.
- A bad seal, insufficient liquid, or a blocked valve. There must be enough liquid to generate steam in the first place.
- Everything tastes flat despite being tender.
- Nothing was browned first. There is no browning inside, so the searing must happen before the lid goes on.
Recovering it
Undercooked is easy — reseal and give it a few more minutes. Overcooked is not recoverable and is the characteristic failure of this tool, so err short and check. A watery sauce is fixed by removing the lid and reducing on the hob afterwards, which most pressure cookers allow directly. If it will not come to pressure, check the gasket and the vent before anything else.
It carries to
Recipes using it
Generated from recipe step verbs and ingredient preparation forms. It is never authored, and it cannot drift from the recipes.