Posted by Go to the bottom of the post to see my recommended methods for cooking rice.
This week, I resolved that for the new year I would start blogging more frequently. Given that I really haven’t been blogging at all recently, that shouldn’t be too hard. I won’t bore you with the various reasons why blogging has been so slow recently, but it seems that starting a new job and a new life in a new city has upended my old routines. One activity that I have been focusing much more effort on in my new life, though, is cooking. Spurred in part by reading Ratio by Michael Ruhlman, I’ve been trying to elevate my cooking from a practicality to an art and even, in some cases, a science (at the very least I’m trying to be more systematic about it).
The other day, I was thinking quite a bit about one of the first items I learned to cook many years ago: rice. I spent the summer between my sophomore and junior years of college in Australia, and most of that time I lived in a hostel. For the first time in my life I found myself really out on my own (I had lived in the dorms my first two years of college), so I realized that I finally needed to learn how to cook for myself. Hostel cooking was more about practicality than anything else, but I picked up quite a few skills that have served me well since then.
Early on, one of my friends in the hostel showed me a pretty straightforward and effective way to cook rice. She would add her rice to unheated water, then heat both together to a low boil in an uncovered saucepan. Once the excess water had boiled off (about 15 minutes), she would then cover the pan, turn the heat very low, and then let the rice “steam” for another 15 minutes or so. This was a long time ago, so I may not be remembering her method totally correctly, but I believe she used a 2:1 volume ratio of water:rice (i.e. 1 cup rice, 2 cups water; this is also the ratio given on the package of rice I currently have in my cupboard). This technique–which I’ll call the “open-pan” method–served me pretty well, but it didn’t always work perfectly, for reasons I’ll describe shortly. Cooking rice in general isn’t too tricky, but you still have to get it right; if it’s undercooked it will be hard and slightly crunch, and if it’s overcooked it will be mushy and soupy–in either case totally inedible.
Although my friend’s open-pan method didn’t always work perfectly, it had its advantages. Firstly, it didn’t require accurately timing the different steps. The rice was ready to be covered when the water had boiled off, and the amount of time it sat closed on low heat didn’t seem to matter too much, as long as it was at least about 10 minutes and not much more than about 30. A more common method of cooking rice is the “closed-pan” method, which involves bringing the water to a boil, then adding the rice and cooking on low heat (for about 20 minutes, according to the packaging on my rice, until all excess water has boiled away). Using this method, however, you’ll be much more likely to have problems with boiling over. Also, your results will depend quite a bit on how much steam escapes during cooking, whereas your results should be more consistent using the open-pan method. Traditionally, one would wait until the water begins boiling before adding the rice, so not having to wait for a boil is another advantage of my friend’s open-pan method. Of course, one could devise a variety of hybrid methods by combining different aspects from either method, but in this post I’ll just compare my friend’s open-pan method with a traditional closed-pan method.
As mentioned above, the open-pan method also had its problems. Specifically, on occasion I found the rice undercooked toward the end of the process, causing me to have to add additional water and extend cooking. The other day, for example, I was cooking 1/2 cup of rice using 1 cup of water. After the excess water had boiled away, the rice was still very hard and undercooked. So, I added an additional 1/2 cup of water, let that boil until the excess was gone, and then I proceeded as usual. The final product came out just right.
Since I’m trying to be much more systematic about my cooking, I decided to figure out what exactly was going on here and to come up with a better formula for determining an optimal water:rice ratio. Previously, I had been working with the formula:
Vw = 2 Vr
where Vw corresponds to the volume of water and Vr to the volume of rice. But, conceptually, such a formula shouldn’t work for the open-pan method anyway, because some of the water will be absorbed by the rice, and some will be boiled away. So, I hypothesized that a better formula would be:
Vw = A Vr + B
where A and B are constants. Based on my experience up to that point, I started with the values A = 1 and B = 8 oz., which meant that the rice would absorb a volume of water roughly equal to the volume of rice, and about 1 cup of water (8 oz.) would boil away. There wasn’t a specific reason for choosing these numbers, other than that they melded with what I had previously observed. The cup of excess water would basically determine the cooking time of the rice, which I assumed would absorb a constant volume of water (relative to the amount of rice present), although this assumption turned out not to be totally correct.
Being the empiricist that I am, I decided to test this formula by cooking 1 cup of rice in 2 cups of water, using the open-pan method, weighing the rice before and after cooking. If my hypothesis was correct, the rice would come out perfectly cooked, weighing 8 ounces more than before it was cooked. This, of course, would not prove that my hypothesis was correct, and many additional trials using different volumes of rice and different water:rice ratios would be needed to have reasonable confidence in my final conclusion… but a single person can only consume so much rice! This experiment (along with all others reported here) was performed on white long grain rice. Results could differ for different types of rice, different cooking surfaces, and different pans. The rice was neither rinsed nor soaked before cooking, which would also change the results.
I found that in this trial (“Trial 1″), my 1 cup of uncooked rice weighed 6.1 oz. and weighed 17.9 oz. after cooking. Thus, it absorbed 11.8 oz. of water, roughly 1 1/2 times the original volume of rice. During this process, the rice roughly tripled in mass. Most importantly, this rice came out cooked just right! But, the rice absorbed more water than I had initially predicted.
I decided to perform a second trial (“Trial 2″), this time to see just how much water rice could absorb. For this trial, I cooked 1/2 cup of rice with 3 cups of water. This rice, which weighed 3.2 oz. absorbed an additional 10 oz. of water, quadrupling in mass. Not surprisingly, this rice was mushy, soupy, overcooked, and totally inedible.
So, I learned that rice can absorb quite a bit of water, but it’s just about right when it absorbs about 1 1/2 times its initial volume (or 2 times its initial mass). So, as a general rule, for the formula:
Vw = A Vr + B
A = 1.5, and 4 oz. < B < 6 oz.
More precisely, one could express these amounts in terms of mass, where, for the formula:
mw = C mr + D
C = 2, and 4 oz. < D < 6 oz.
But, what about the traditional closed-pan method? In this case, I assumed that the value of the second constant (B or D) would be zero, since keeping the lid on the pan should prevent water from escaping, causing all of it to be absorbed by the rice. But, as a first test (“Trial 3″), I decided to follow the directions on my package of rice (2:1 water:rice ratio, bring to a boil, then keep at low heat for 20 minutes), cooking 1/2 cup of rice with 1 cup of water. In this case, the 3.1 oz. of rice absorbed 6.5 oz. of water–1.6 times the initial volume of rice. This rice came out almost right, although it was slightly wet and overcooked–but just slightly, and it was still edible.
So, I decided to conduct one last closed-pan trial (“Trial 4″), this time with 1/2 cup of rice and 3/4 cup of water. Here, 3.1 oz. of rice absorbed 5.1 oz. of water. This rice came out better than in Trial 3, but it was just very slightly hard.
It turned out, then, that even with the pan closed, a small amount of water was still lost, although perfectly cooked rice still absorbed about 1 1/2 times its initial volume in water. Thus, for this method, given the formula:
Vw = E Vr + F
E = 1.5, and F = 1 oz.
In terms of mass, given the formula:
mw = G mr + H
G = 2, and H = 1 oz.
These findings are, of course, only fully applicable to my own kitchen setup. However, they should be still be reasonably broadly applicable. I think that the value of the first constant (A, C, E, or G; 1.5 for volume formulas, 2 for mass formulas) should always be true, at least for this type of rice (white long grain). The mass formulas will be the most broadly applicable, but the volume formulas should generally work. The value of the second constant (B, D, F, or H) could vary more depending on your specific setup, so it might require more refining. In particular, this constant will need to be increased as you move to a larger pan with greater surface area.
The results of all of these trials, plus some of the “preliminary experiments” mentioned above, are summarized in the following table:
| Trial | Method | Vr (fl.oz.) | Vw (fl.oz.) | mr (oz.) | mr+w (oz.) | mw,abs (oz.) | mw,abs:mr | Vw,abs:Vr | Result |
|---|---|---|---|---|---|---|---|---|---|
| -2 | open | 4 | 8 | undercooked | |||||
| -1 | open | 4 | 12 | good | |||||
| 1 | open | 8 | 16 | 6.1 | 17.9 | 11.8 | 1.9 | 1.5 | good |
| 2 | open | 4 | 24 | 3.2 | 13.2 | 10.0 | 3.1 | 2.5 | overcooked |
| 3 | closed | 4 | 8 | 3.1 | 9.6 | 6.5 | 2.1 | 1.6 | OK, slightly wet |
| 4 | closed | 4 | 6 | 3.1 | 8.2 | 5.1 | 1.6 | 1.3 | good, just slightly hard |
Based on the experiments above, I can recommend two methods for cooking rice. The key to both of these, though, is that they don’t involve just a simple water:rice ratio, as described below. In either case, these are specifically for cooking white long grain rice.
1. Open-Pan Method
Add rice and unheated water to a small saucepan, and bring to a boil. Continue at a slow boil stirring occasionally just in the beginning. Once almost all of the excess water has boiled away, and the rice mixture has a dimpled appearance and no longer moves freely, turn the heat to very low and cover the pan. Do not uncover until you’re ready to serve! Keep heating for about 15 minutes, but not more than about half an hour.
To determine how much water to add to your rice, take the volume of rice and multiply it by 1.5. Then, add an additional 1/2 to 3/4 cup of water. For example, to cook 1 cup of rice, you’ll add 2 to 2 1/4 cups of water (1.5 x 1 cup + 1/2 [or 3/4] cup). For larger pans, you may need to increase the amount of excess water beyond 3/4 cup.
2. Closed-Pan Method
Bring water to a boil in a small saucepan, then add rice and cover the pan. Once boiling resumes, turn to low heat and heat at a low boil for 20 minutes (or until all visible excess water has been boiled away for at least about 5 minutes).
To determine how much water to add to your rice, take the volume of rice and multiply it by 1.5. Then, add an additional 1 oz. of water. For example, to cook 1 cup (8 fl. oz.) of rice, you’ll add 13 oz. of water. These values are for a small saucepan, and for larger pans you will certainly need to increase the amount of excess water you add. You may also need to increase this amount if the lid does not form a tight seal with the pan.
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