Rice is one of the easiest things to cook, but many people are afraid of it because they’re turned out overcooked soggy mushy rice in the past, and don’t know how to fix that. The problem is that there are so many recipes available for such a simple thing, and all of them are different. One recipe printed right on the plastic bag of rice I bought calls for 2 cups of water per cup of rice, another says only 1 cup of water is needed. Others say you should use 1.5 cups of water per cup of rice.
Some recipes don’t even measure water in cups, they just say “add water until the level is about 1/2″ above the level of the rice in the pot”. Some call for pre-soaking rice, others say you should never pre-soak.
So who is right? Why so much variation? You could follow two recipes on the web, and produce perfect rice with one and mushy crap with the other. Does that mean one was good and the other was bad? Maybe for you, but it’s possible that for someone else, the results are reversed, and the crappy recipe produces perfect rice, while your perfect recipe doesn’t.
The reason is because even if both of you follow the recipes exactly, there are still differences in the cooking range/stove you used, the pot you used to boil the rice, the exact amount of heat, etc. No cookbook or recipe can account for all these differences. This is why people’s results can vary so much.
I like a bit of math and science in my cooking, so I decided to put together this post. At the very least, it’ll explain why people’s results vary so much and why recipes are so different. Hopefully, it’ll help you produce perfectly cooked rice every time, without any guesswork.
What happens when rice cooks?
Uncooked dry rice grains have some moisture, but not a lot. The usual rice you buy in stores, both long grain and short grain, has about 12% moisture content, meaning each grain is 12% water by weight. Aged rice has a lower moisture content. If you buy aged basmati rice, for example, the moisture may be as low as 7-9%, depending on how long it was aged.
Cooking does two things to the rice. First, it hydrates the rice grain (adds moisture to it), making it swell and increase in size. Second, the heat cooks the rice grains, making them soft and slightly gelatinous.
Properly cooked rice has a moisture level between 58% and 64%. Anything below that range will feel hard and uncooked, and anything over that range will be mushy. You may prefer one end of the range rather than the other, depending upon the type of rice and your personal tastes.
So the goal of cooking is to increase the water content of the rice from 12% to about 60%, and also heat the interior of each grain for a sufficiently long period that it is cooked.
How much water should you add?
Water is used for two things – to hydrate and cook the rice, and to make up for water losses during cooking. The amount of water needed to hydrate the rice is fixed and based solely on the amount of rice, and can be calculated based on desired hydration levels. But the water lost during cooking is very variable, and depends on things such as:
- length of cooking time
- temperature of rice during cooking
- shape and size of the pot in which the rice is cooked
- how tightly the lid fits on the pot
Water for hydration
Let’s start with the easy part first, which is water needed for hydration.
Normally, we measure rice and water in cups. One cup of water is 240 ml, or 240 grams. One cup of rice varies, depending on the type of rice:
1 cup long grain rice = 185 – 190 grams
1 cup short grain rice = 195 -210 grams
Short grain rice can be packed tighter in the cup, so 1 cup of it weighs more than the same volume of long grain rice.
In order to hydrate this, we need:
1 cup short grain rice = 0.94 to 1.24 cups of water (for 58% – 64% hydration)
1 cup long grain rice = 0.85 to 1.12 cups of water (for 58% – 64% hydration)
You can pick the middle of the range and say that 1 cup of long range rice needs 1 cup of water for hydration, while 1 cup of short range rice requires a bit under 1.1 cups of water for hydration.
Water losses during cooking
Next we need to figure out how much water will be lost during cooking, and make up for that. Water is lost during cooking due to evaporation. Ideally, we want to lose as little water as possible to evaporation. We can do this by:
- use pots which have tight fitting lids
- choose pots which are narrow and tall, rather than short and wide
- use high heat to bring water to a boil quickly, then immediately lower heat to simmer
- try to minimize cooking time
Consistency is the key to cooking rice, so don’t use a different pot each time you cook rice. Pick one pot and stick to it, so you can learn its quirks and adjust accordingly for them. The most important feature is should be the lid – pick one that has a tight fitting lid that doesn’t allow much steam to escape. The heavier the lid, the better. A tall and narrow pot will lose less steam than a wide and shallow pot.
Rice needs to cook at a simmer, which is a point just short of a boil. The temperature of a “simmer” is not that much lower than a boil, it’s just that the rate of heat delivery is such that the temperature is barely maintained, rather than having to keep losing excess heat through big clouds of steam. A “simmer” would be about 94-98 °C, as opposed to a boil which is 100 °C.
The easy way to do this is to bring the rice and water to boil, then reduce the heat drastically until it’s just enough to make bubbles slowly pop at the surface, and to produce a thin cloud of steam on the surface. Cooktops vary, so you will need to find the simmer setting on yours. On a typical cooktop that goes from 1 to 10, simmer might be somewhere between 1 – 3. You have to experiment and find out.
To reduce total cooking time, it’s important to bring the rice to a boil quickly. So use the high heat setting on your stove (and stand there and watch, or at least, don’t leave the stove for prolonged periods). As soon as it comes to a boil, reduce heat to simmer, and let it cook covered for the recommended amount of time.
To pre-soak or not?
This factors directly into cooking time, so I’m going to mention it here. In fact, we can also ask “should we wash the rice or not” while we’re at it.
What’s the difference between washing and pre-soaking? In washing, you add water to rice, swirl it around with your fingers, then drain the water out. Washing removes any loose starch grains adhering to the rice, and also removes any vitamins that the rice has been fortified with.
In the US, by law, all rice is sold fortified with certain B vitamins. This may or may not be useful to you. If you have a varied diet, if you occasionally take vitamin/mineral supplements, or if you already eat other foodstuffs supplemented with vitamins (anything made from flour, cereals, etc. will have added B vitamins), then you don’t really need the little bit of vitamins that were artificially added to the rice.
I always wash rice for 2 reasons:
- washing gets rid of loose starch granules, which make rice sticky after cooking
- washing can get rid of dirt and dust, after all, rice is a raw agricultural product
As I said, the downside is that you also lose those added vitamins. I don’t care about them because they are very minor, and I get enough vitamins from other foods anyway.
Now, what about pre-soaking? Yes, rice can be pre-soaked without washing. All you have to do is to not add an excess of water during the pre-soaking, so you don’t have to throw any water away. This way you can pre-soak, and then use the same water for cooking. Any vitamins that leach out remain with the water, and so are absorbed back into the rice when it cooks.
I think pre-soaking is a must, if you have the time. For any kind of rice, pre-soaking will always reduce the cooking time. Why? Because pre-soaking “wets” the interior of the rice grains, which allows them to cook much faster and more evenly.
When you cook rice, the heat has to get from the outside of the grain to the interior. This can take time. Let’s say you cook the rice for 15 minutes. While the outside of each grain reached cooking temperature right when you brought the heat down to a simmer, the inside doesn’t reach full cooking temperature until much later. So you can have the outside cooking for 15 minutes while the inside only cooks for 5 minutes. This means that either the inside is not fully cooked, or else the outside is overcooked and mushy.
Soaking allows water to reach the inside of the grains, which greatly improves heat transfer into the grain. So the inside starts cooking much sooner, compared to rice that wasn’t pre-soaked. This allows the total cooking time to be reduced, and for each grain to be cooked as evenly as possible.
Remember, the shorter the total cooking time, the less water you will lose during cooking, and the better the rice will taste, all else being equal.
So in summary, my recommendation is:
- Always wash the rice first in a couple changes of cold water, specially if you are cooking long grain rice. Long grain rice should not be sticky, and washing makes it less sticky at the end.
- Always pre-soak rice in cold water for about an hour, if you have the time. It will make the rice cook much more evenly, and can reduce cooking time in half.
You may choose not to wash or pre-soak the rice, but in that case, keep in mind the caveats mentioned above.
So, how much water do you need?
To figure the total amount of water needed, you should add the water required for hydration and the water losses during cooking. For long grain rice, you need 1 cup of water for 1 cup of rice, and for short grain rice you need 1.1 cups of water per cup of rice. This is hydration water only.
Next, you need to add water for cooking losses. This will vary greatly with your setup, the size and width of the pot, the lid, the temperature, etc. All those things mentioned above. If you wanted to be very exact, you could even perform an experiment:
- Fill the pot with a measured amount (say 3 cups) of water – water only, no rice. Close the lid, put it on the stove, bring to a rolling boil.
- Immediately lower the heat to simmer, and note the time.
- Wait for 30 minutes, then turn the heat off, and remove the pot from the stove. Let it sit on a counter top while it cools to room temperature.
- Measure the amount of water left in the pot.
Let’s say you started with 3 cups and you end up with 2 cups after 30 minutes of simmer. So your rate of water loss due to evaporation was 1 cup per 30 minutes. So if you expect to cook your rice in 15 minutes, you should plan for 1/2 a cup of lost water during cooking. For cooking 1 cup of long grain rice, you would add 1 cup of water for hydration plus 1/2 a cup for water loss, making 1.5 cups of water per cup of rice, for example.
If you don’t want to measure the rate of water loss, you will have to discover the right amount of water through trial and error. Here’s some brief pointers on how to begin:
All cooking times are measured from the point when you turn the heat down to simmer.
Rice that has not been pre-soaked typically cooks in 15 – 20 minutes, while rice that has been pre-soaked cooks in about 8-10 minutes.
If your pot is really bad in terms of retaining heat (loose fitting lid, too wide and shallow), it will probably lose about a cup of water to evaporation over the 15-20 cooking time of non-pre-soaked rice. This is the maximum amount of water you should start with (for example, cooking 1 cup of long grain rice = 1 cup water for hydration + 1 cup water losses = 2 cups water total). Chances are, your pot isn’t that bad, so you need to adjust down from 1 cup.
Typically, the range is:
- the best professional dedicated rice cookers – very tight lids, zero water loss
- the worst random lidded pot found in the average kitchen – about 1 cup water loss per 20-30 minutes
- pot without a lid – all bets are off, your mileage will vary. Not recommended at all.
Depending on the pot you use, you’ll be somewhere in that zero to one cup range for water loss. I’d split the difference and figure on half a cup of water loss and adjust up or down from there through trial and error.
A note on proportions
Unless you cook exactly 1 cup of rice at a time, you will need to scale these amounts up or down. Let’s say you figure out through trial and error (or through the procedure described above) that you need exactly 1.5 cups of water per cup of long grain rice to make the perfect rice. Now let’s say you decide to cook for friends, so you end up cooking 3 cups of rice instead of 1. Can you scale up the water from 1.5 cups to 4.5 cups (3 x 1.5)?
If you’ve read this far, you know the answer is NO.
Remember, only the water needed for hydration scales with the amount of rice. The water needed to cover water losses only scales with the cooking time, not with the amount of rice.
When you arrived at that 1.5 cups water per 1 cup rice number, what you were really doing was using 1 cup of water for hydration, and 1/2 a cup of water to cover water losses during cooking. So when you scale this up to 3 cups of rice, you will need 3 x 1 = 3 cups of water for hydration, but still only 1/2 a cup of water to cover water losses during cooking. Water losses during cooking only depend on the length of cooking time, and that hasn’t changed. Yes, it will take longer for 3 cups of rice plus water to come to a boil than it took for 1 cup of rice plus water to come to a boil, but we don’t measure that time anyway, we measure cooking time from after it’s come to a boil and the heat is reduced to simmer. This time doesn’t change whether you’re cooking 1 cup of rice or 3.
So in this case the correct amount of water needed for 3 cups of rice was 3.5 cups, and if you used 4.5 cups based on the simple calculation of multiplying everything by 3, then you used too much water and your rice will be soggy and mushy. This is one of the commonest mistakes that people make and why rice so often turns out bad.
In this respect, the older method of describing water quantity by “inches of water covering the rice was better. The idea there is that water mixes with rice in a roughly 1:1 proportion, and the water level above the level of the rice represents water that will be lost during cooking. So if you know half and inch of water is lost during cooking, then no matter how much rice you have in the pot, half an inch of water on top of that will still be the cooking losses.
This method is also very hit and miss when it comes to sharing recipes, because nobody can say “half an inch on top of the rice works well” without seeing the pot you’re cooking with. This is because half an inch of a wider pot is a lot more water than half an inch of a narrow pot. If you use the same pot regularly, then you may make an observation that half an inch works well for that pot, or maybe 1/3 of an inch, or 2/3rd. This can serve you well for as long as you use the same pot, you’ll never have to measure water anymore. Just drop in the rice, add enough water to cover the rice plus 1/2 an inch over, and you’re all set. But if you change pots, you’ll need new numbers for the new pots. I don’t like this method much because eyeballing half an inch isn’t very accurate, I get much better results with measuring volumes in a measuring cup. But it still beats scaling up single cup recipes naively, without separating out water of hydration and water losses of cooking.
What’s a good cooking time to aim for?
Rice tastes best when it’s cooked in the shortest time possible, but evenly (inside/outside of each grain cooked to the same degree).
Pre-soaking reduces cooking time, and for this reason alone I think it’s worth doing whenever you have the time to pre-soak. Always pre-soak for at least 1 hour.
Washing rice is generally a good idea, unless you are making certain short grain varieties that are meant to be sticky. In which case I would still pre- soak, but not wash (not drain the pre-soak water, just use it for cooking).
In my kitchen, when cooking basmati rice (my favorite) which has been pre-soaked for 1 hour, it takes about 8-10 minutes to cook the rice. The time is measured from after I’ve brought the pot to a rolling boil and lowered the heat to a simmer.
I use a heavy stainless steel pot for cooking rice. Since I have an induction cooktop which requires ferromagnetic pots, the pot is actually triple layered (magnetic stainless steel on the bottom, copper in the middle, regular stainless steel on the inside). I bring the pot to a boil on high heat (the highest setting on the cooking range), then immediately lower the heat to a simmer. The cooktop can be set by power level ( 1 to 10) or by temperature, and I set the simmer by temperature at 210 °F (boiling point is 212 °F). This is what I would call a “high simmer”, meaning that it cycles between just below boiling to a mild boil and then drops down again. A low simmer would be more like 200 °F. At these settings, it takes 8-10 minutes of simmer to cook the rice, regardless of the quantity of rice.
After cooking, always leave the rice on the stove (just turn the heat off), and let it sit covered and undisturbed for about 10 minutes before serving.
