Pressure Cooker — The Complete Guide

Tough cuts and dried beans, transformed in 30 minutes — the science and practice of pressure cooking.

A pressure cooker is a sealed pot that traps steam, raises the internal pressure above atmospheric, and lifts the boiling point of water from 100°C to roughly 121°C. That extra 21°C is the entire point: collagen-rich cuts of meat that need three hours in a regular pot break down in 45 minutes; dried beans that need overnight soaking and 90 minutes simmering go from dry to creamy in 35 minutes flat. Modern electric pressure cookers (Instant Pot and friends) added timers, safety locks, and the ability to brown food in the same pot you cook it in. The cooking science did not change — pressure cookers have been doing this for a century — but the user experience finally caught up.

This guide covers what is actually different about pressure cooking versus other methods: timing (much shorter), liquid (often less than you would think), and the things that do not pressure-cook well (delicate fish, anything you want crispy). KitchenConvert handles the conversion side. Paste a slow-cooker recipe and the app will tell you what to adjust for pressure cooking — usually less liquid, shorter time, and watching for natural-versus-quick-release. Adapt a traditional braise from a French cookbook and KitchenConvert converts cups to grams, Celsius to whatever your pot displays, and scales the servings to fit your six-quart or eight-quart pot. None of that replaces understanding the technique, which is what the rest of this guide is for.

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Frequently asked questions

What is the difference between a pressure cooker and a slow cooker?

A pressure cooker raises the cooking temperature above 100°C by sealing steam in, so food cooks faster. A slow cooker holds food at 75-95°C for many hours, so collagen breaks down gradually. Both produce tender braised meat — the pressure cooker does it in 45 minutes, the slow cooker in 8 hours. Most modern multi-cookers (Instant Pot etc.) do both functions in one device.

Is it safe to use a pressure cooker?

Yes — modern pressure cookers have multiple redundant safety mechanisms: a lid lock that will not open under pressure, pressure-release valves that vent automatically if pressure exceeds the safe range, and overheat sensors that cut power. The "exploding pressure cooker" stories nearly all involve mid-20th-century stovetop models with one safety valve. Follow the manufacturer maximum-fill line (usually 2/3 full, 1/2 for foods that expand like beans and pasta) and you are fine.

How long does it take to come up to pressure?

8-15 minutes for most electric pressure cookers, depending on volume and starting temperature. Cold ingredients straight from the fridge take longer than room-temperature ones. The displayed cook time (e.g. "20 minutes for chicken thighs") does not include the pressurise time, so plan on real elapsed time being 30-40 minutes including come-up and natural release. Stovetop pressure cookers come up faster but require more attention to the burner.

Can I cook frozen meat in a pressure cooker?

Yes, with adjustments. Add 50% to the cook time, browning frozen meat is impossible so skip the sauté step, and use enough liquid to surround the frozen mass — solid frozen meat will not heat evenly otherwise. The texture is usually slightly worse than starting with thawed meat, but for a weeknight stew with frozen chicken thighs at 5pm, it is perfectly adequate. Frozen ground meat is the one exception — break it up under cold water first.

Why is my pressure cooker not sealing properly?

Four common causes, in order of probability: the silicone gasket ring is misaligned or torn (replace yearly), there is food residue on the rim preventing a seal (wipe clean), the float valve is gunked up (lift it out and rinse), or the lid is not fully locked into position (rotate until it clicks). If your cooker hisses continuously without building pressure, it is nearly always the gasket. Replacement rings cost $10-25 — keep a spare.