The Science of Cooking Rice - FineCooking.com

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The Science of Cooking Rice

illustration by Alex Nabaum

illustration by Alex Nabaum

  • illustration by Alex Nabaum

By Fine Cooking Editors, editor

July 7th, 2010

By David Joachim and Andrew Schloss
from Fine Cooking #106, pp. 32-33

We've cooked rice countless times and countless ways, but we still don't always get it right. We've rinsed it, soaked it, simmered it in carefully measured liquid, and boiled it in a large pot of water. We've cooked it with and without a lid, tried all shapes and sizes of pans, and even invested in specially designed rice cookers. Sometimes each grain is tender yet chewy, separate, and fluffy. Other times, the grains just clump together.

So how do we get our rice to behave and turn out exactly how we want it? Well, we've found the secret. Cooking rice perfectly is simply a matter of choosing the right variety and the right cooking method for the type of dish you want to make. It's not rocket science, just a simple application of rice science.

Everything You Need to Know About Rice
Download a detailed chart on How to Cook Rice, including 14 varieties and 5 common cooking methods, and watch a video detailing step-by-step how to cook rice.


Why isn't there a one-size-fits-all cooking method for rice?
There are myriad rice varieties, and each has a unique chemistry, starch content, shape, and size (such as long grain, medium grain, or short grain). These factors affect the amount of liquid required and the rate at which the rice cooks. The type of dish you're making also affects the cooking method. Different dishes-risotto, paella, rice pudding, plain steamed rice-call for different techniques to produce specific results.

It isn't quite the free-for-all it appears to be, though, because certain varieties of rice are best suited to certain preparations. For instance, cooks in India tend to use long-grain rice and boil it in plenty of water to create separate grains that remain perfectly intact. The Chinese use starchier medium-grain varieties so that the rice sticks together, making it easier to pick up with chopsticks. The Spanish also use starchy medium-grain varieties, but they cook the rice with stock instead of water and add meat, fish, and vegetables to make paella. Italians use even starchier rice and stir it during cooking to create creamy risotto. And cooks in Thailand use very sticky short-grain rice (glutinous rice) to make rice pudding sweetened with coconut milk and topped with mango slices.

Why do some recipes call for soaking and/or rinsing rice and others don't?
When rice cooks, two things happen: Water gets absorbed into the grain, and heat softens the starch. Soaking rice speeds up the cooking by kick-starting the absorption of water before the rice even enters the pot. By letting rice soak for 30 minutes or so, you can reduce the cooking time of most rice varieties by about 20 percent.

Soaking rice can also affect the flavor of the finished dish. Acetylpyrroline, the flavor component in aromatic rice varieties (such as jasmine, basmati, wild pecan, Wehani, and Texmati) that is mainly responsible for their characteristic popcorn-like aroma, dissipates during cooking. The longer your rice is over the heat, the less aromatic it will be. So by soaking the rice and shortening the cooking time, you get more flavorful results.

Rinsing rice, on the other hand, alters its texture when cooked. When you want perfectly separate grains, rinsing removes the thin layer of starch from the surface of each grain and helps keep the rice from sticking together. Long-grain rice, like basmati, is often rinsed for this reason.

The only types of rice that should not be rinsed are those that have been enriched. Vitamins and minerals are sprayed onto the surface of enriched rice to replace those lost during processing, and rinsing will wash a lot of these nutrients away. Most of the commercially milled white rice in the United States is enriched-check the label if you are unsure.

Why do you have to make risotto with Arborio rice, and why does it have to be stirred?
If you didn't use Arborio or another risotto rice, it wouldn't be risotto, because its defining characteristic is the texture of the rice. Risotto rice contains a high amount of a starch called amylopectin. The more amylopectin that's packed into the grains, the softer and creamier the rice becomes during cooking. Arborio, carnaroli, baldo, Roma, Vialone nano, and other risotto rices contain just the right amount of amylopectin to render the grains perfectly creamy on the surface yet chewy and al dente in the center. If you tried to make risotto with long-grain white rice, it would be too thin because of the lack of starch. And if you used a very high-starch glutinous or sticky rice, the grains would entirely disintegrate, and you would end up with a thick, gloppy mass.

The right type of rice isn't the only factor in preparing a perfect risotto; it also depends on the way the rice is cooked. A risotto must be cooked without a lid and stirred throughout the cooking process. A large amount of cooking liquid, often a flavorful stock, is added in stages. Stirring roughs up the surface of the rice, releasing starch into the cooking liquid. The starch acts as a thickener and creates a creamy texture. And because risotto is cooked without a lid, the liquid evaporates and concentrates the flavors.

You may have come across recipes for baked risottos that boast a no-stirring method. In our opinion, these don't work. When you add all the stock at once and then cook the rice in the oven undisturbed, much less starch is released from the grains, as there is no friction from stirring to facilitate this process. The result is very little creaminess. Butter, cream, and cheese are often added in abundance to enhance and enrich the texture; however, the final risotto won't have the same velvety feel of one that's thickened with loosened starch from the rice.

Parboiled Rice, Uncovered
For all the rice varieties available at the grocery store, it's surprising how much shelf space is given over to parboiled rice. Also known as converted rice, parboiled rice has been pressure-steamed and then dried in its natural outer husk (which is later removed). This process hardens the starch in the grains so they remain firmer, less sticky, and separate when cooked. It also forces the vitamins and minerals from the outer layer of the grains into the endosperm, which is the part we eat. This makes parboiled rice a more nutritious option than regular (unenriched) white rice, which doesn't retain any of the goodness of the nutrient-rich husk.

 

Test the Science: 

Basic Fluffy White Rice Basmati Rice Pilaf with Pistachios Brown Rice with Walnuts and Golden Raisins
Basic Fluffy White Rice   Basmati Rice Pilaf with Pistachios   Brown Rice with Walnuts and Golden Raisins



posted in: Blogs, food science, rice, cooking rice
Comments (1)

Pielove writes: Great article, but what really tickled my fancy was the illustration-- those little dancing grains and water droplets, plus the "TO RINSE..." banner. I want to see more from Alex Nabaum! Posted: 12:57 pm on July 12th

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