Pressure cooker patented by Denis Papin, France, 1679 (the 'steam digester'); commercialised for domestic use in the 1930s; modern electric pressure cookers proliferated globally from the 2000s
Pressure cooking uses sealed vessel design to raise the boiling point of water above 100°C, allowing cooking temperatures of 115–122°C that dramatically accelerate reactions that depend on temperature — particularly collagen-to-gelatin conversion, starch gelatinisation, and Maillard development in certain applications. The technique reduces conventional braise times by 60–70% without compromising texture when used correctly. The physics are simple: in a sealed vessel, steam cannot escape, so pressure builds. Under pressure, water requires more energy to reach boiling point — at 103 kPa (15 psi, the standard domestic pressure cooker operating pressure), water boils at approximately 121°C. At this elevated temperature, collagen hydrolysis — which proceeds relatively slowly at 90°C — accelerates significantly. The Van't Hoff rule approximates that reaction rates double for every 10°C rise in temperature, meaning cooking at 121°C could theoretically be 4x faster than at 90°C for temperature-sensitive reactions. For braising: tough collagen-rich cuts (chuck, brisket, oxtail, lamb shoulder, pork belly) that require 2.5–4 hours of conventional low braising can typically be pressure-cooked in 45–75 minutes to achieve equivalent collagen conversion and tenderness. The sealed environment also prevents evaporation, concentrating the braising liquid without adding additional liquid during cooking. The critical limitation is colour and crust: the Maillard reaction that develops deep seared surfaces on braised meats occurs at low water activity and high temperature — conditions incompatible with pressure cooking's moist, high-humidity interior. Always sear thoroughly before pressure cooking to develop flavour, then use the pressure cook for the braising phase. Modern electric pressure cookers (Instant Pot and equivalents) operate at slightly lower pressure than stovetop models (approximately 70 kPa vs 103 kPa) and consequently at lower temperatures, extending cook times by approximately 20–30% compared to stovetop pressure cookers.
Pressure braising produces deeply tender, collagen-rich results with concentrated braising liquid — flavour is slightly more 'stewed' than slow-conventional braise due to sealed evaporation
Pressure cooking at 103 kPa raises water boiling point to 121°C, accelerating collagen conversion by approximately 3–4x compared to conventional braising Always sear before pressure cooking — the sealed moist environment cannot develop Maillard browning on meat surfaces Never fill the pressure cooker more than two-thirds full — liquid expands with heat and foam can block the pressure release valve Reduce braising liquid separately after pressure cooking if concentration is needed — the sealed vessel prevents natural evaporation For delicate proteins (fish, eggs, soft vegetables), use far lower pressure settings or very brief cook times — pressure cooking overcooks delicate products easily Always allow full natural pressure release for large cuts of meat — rapid release causes pressure gradient that can dry and toughen exterior
For maximum flavour in pressure-cooked braises, deglaze the searing pan separately with wine and add to the pressure cooker — don't lose the fond For stock production, pressure cooking extracts collagen from bones in 1.5–2 hours versus 6–8 hours by conventional methods — a dramatic time saving Cook grains and legumes in pressure cookers without soaking — chickpeas cook from dry in 35–40 minutes at high pressure For ultra-smooth hummus, pressure-cook chickpeas beyond tenderness to complete softness — over-cooked chickpeas blend to a creamier paste Add dairy only after pressure cooking — cream, milk, and cheese can curdle or foam violently under pressure and heat
Skipping the sear before pressure cooking, producing meat with excellent tenderness but no flavour-developing Maillard crust Filling the vessel above two-thirds capacity with liquid, risking blockage of the pressure relief valve and potential safety hazard Opening with rapid pressure release for large braised cuts — rapid depressurisation can toughen the exterior of long-cooked meats Pressure cooking cuts that are genuinely too lean to benefit — lean proteins become dry and stringy under extended pressure Expecting pressure cooking to replicate conventional braising flavour exactly — the sealed environment produces a subtly different profile