# When cooking in a stove-top pressure cooker, is the time to cook a particular food item the same, irrespective of the quantity?

I was searching online for how much time is needed for cooking 1/2 kg of rice in a stove-top pressure cooker and came across this guide - How Long Does it Take to Cook Rice in a Pressure Cooker? It has a table that shows how much water to add for 1 cup of rice, and how much time it will take for the rice to be fully cooked (time measured after pressure builds up in the cooker).

My doubt is whether the cooking time in a pressure cooker remains the same irrespective of the quantity of food - does 2 or 3 cups rice also take the same amount of time to cook as 1 cup of rice?

The timing in pressure cookers, simmering, stewing, boiling, frying, sous vide, and similar cases of cooking in a fluid, is mostly a function of the size of the bits (assuming that they’re not packed together so tightly that the fluids can’t flow between them) and the temperature (and pressure, if you have an adjustable pressure cooker)

As rice is a consistent size, the time won’t change.

It’s actually a function of the time to get everything up to temperature and then the cooking time, so if you’re adding a lot of cold items to cook, then it might affect your timing significantly. Particularly in a slow cooker where it doesn’t heat up quickly. (For those it’s a good idea to start it on high for at least 30 minutes or even an hour, then switch it to low if that’s the level you want to cook at)

Also, things will change if you’re braising or slow cooking with the items not completely submerged.

• Okay, I guess there is one other exception: when you have a major state change, but that’s mostly just in frying when you have moisture causing evaporative cooking
– Joe
Feb 28 at 17:24

Cooking time won't change* with the amount of rice. Keep in mind that much less water is needed in a pressure cooker than on the stove because there is very little evaporation. The ratio of rice to water should be around 1:1 depending on the type of rice (that is, how much extra starch is desired outside the grains, if any — such as for pudding rice).

• Note: Stove-top pressure cookers may add a little time for large batches depending on the power of your range, but probably not much in comparison to the normal length for rice cookery (especially brown rice). Stand-alone pressure cookers (like insta-pot or dedicated rice cookers) use an induction burner which is pretty fast and efficient. For most rice and cookers the time to starting temp won't vary very much between batch sizes. These pressure cookers also have a thermometer built into the base plate that detects a sudden rise in temperature which is what tells it that the water has all evaporated and that it should shut off the burner.
• Good answer - OP is asking about a stove-top pressure cooker, so unlikely to have the thermometer and induction burner built in.
– bob1
Feb 26 at 23:24
• right-o. thank you for the note. Feb 27 at 3:20

Sort of. This applies to all cooking.

Assuming a single main ingredient (i.e. ignoring seasoning), once you have reached a homogenous temperature/pressure in the slow cooker, the food should take the same time, no matter the amount. For rice, the only difference will be in the time it takes to get to temperature - more = longer to get to temp. Once it is boiling and at pressure, it'll be cooked within the time recommended. I've not cooked rice in a pressure cooker for anything other than congee*/zhou/*juk, so I don't know how long this might be.

Obviously, the time taken to reach the homogenous temperature will depend on the volume of pieces in the cooker - for instance a lump of meat 1 litre in volume (61 cu in) will take longer to for the heat to penetrate than a lump 1 millilitre (0.06 in3) in volume, so the bigger will take longer to cook.

However, the temperature of your pot might not be homogenous while at temperature and pressure; the outside content might be boiling and at pressure, but the internal temperature of meat might still be near storage temperature. You commonly see this effect when roasting and frying meats, where the outside might be nicely seared, but the internal can be heated enough to produce a medium rare or rare meat (or even raw, depending on how good a cook the person is).

A pressure cooker enables you to cook water-based recipes at higher temperatures. Non-water-based recipes include deep frying in oil. It works by increasing the pressure, hence the name, and thereby increasing the boiling point of water. When water boils, it turns into steam, leaving the body of water and taking heat with it. When you increase the pressure, water boils at a higher temperature. The well known boiling point of 212 F (100 C) is at sea level. At higher elevations, water boils at a lower temperature. This can be seen in the "High Elevation" instructions in many recipes, especially those on cake mixes.

Now that you are cooking at a higher temperature, the overall cooking time will be less than if you did not use a pressure cooker.

The time to cook additional food items will be proportional to the amount of food and water you add to the pressure cooker because that additional volume must be brought up to temperature. In the case of rice, you will be adding more rice but also more water, both of which will require more time to bring up to temperature. Once the temperature of the contents has been stabilized, the cook time is the same regardless of volume, it is just the time to reach that temperature that is increased.

• The question specified that "time" is time at pressure, meaning after the water reaches the correct temperature. Feb 27 at 20:20