Water for Cooking Calculator

There are two completely different kinds of “how much water” question in cooking, and mixing them up is why so many charts contradict each other.

Some foods absorb everything you give them: rice, oats, lentils. The water is an ingredient, the ratio is a recipe, and getting it wrong ruins the dish. Other foods just cook in water that gets poured down the sink: pasta, potatoes, eggs. There the water is a cooking medium, the amount is about coverage and heat capacity, and being generous costs you nothing except the time it takes to boil.

Water by food type:

Rice here is long-grain white on the stovetop at 1.75 parts water to 1 part rice, which matches the rice to water ratio calculator. Brown rice takes 2.25, sushi rice 1.25, and wild rice 3.5, so if you are cooking anything other than plain white rice go there instead.

Why the amount matters, food by food:

• Pasta wants room to move. The old rule is 4 quarts per pound, and while you can get away with less in a wide pan, a crowded pot drops off the boil the moment the pasta goes in and the starch concentration climbs until the strands weld together.
• Rice absorbs all of it, so the ratio is the whole game. Too much and it is mush, too little and the bottom layer scorches while the top stays hard.
• Oats are forgiving in one direction only. Extra water thins the porridge and you can boil it off; too little and it seizes into a solid mass that no amount of stirring rescues.
• Lentils need enough water to stay covered as they swell, but not so much that you are draining away half the flavour. Cook them like rice with a little slack, not like pasta.
• Potatoes and eggs just need to stay submerged with about an inch (2.5 cm) over the top. Anything poking out cooks unevenly.

Worked example: pasta for 4 people means 16 cups (3.8 litres) of water for 16 oz of dry pasta, which is 454 g or exactly one pound, in a pot of at least 6.5 litres. Rice for 4 means 3.5 cups (0.83 litres) of water for 2 cups of dry rice, which finishes as about 6 cups cooked.

Tips:

• Start potatoes and eggs in cold water so they heat through evenly rather than cooking from the outside in
• Bring pasta water to a full rolling boil before the pasta goes anywhere near it
• Salt at about 1 teaspoon per 4 cups for pasta, and from the start for potatoes so it reaches the middle. Lentils are the exception: salt firms the skins, so wait until they are nearly soft
• Salting egg water does nothing, since the shell keeps it out. A splash of vinegar helps any that crack
• At altitude water boils cooler, so add time rather than water