A survey of common rice-to-water ratios suggests that long-grain rice absorbs more water than short-grain rice and that brown rice absorbs more than white rice. And yet when we researched how rice is cooked commercially, we found that 1 cup of water should be sufficient to hydrate 1 cup of rice, regardless of type. The water in excess of this 1:1 ratio is included to account for evaporation during cooking, according to commercial producers. To find out if this theory holds water, we ran the following experiment.
We gathered 17 different varieties of rice, including white and brown short-grain, medium-grain, long-grain, basmati, and jasmine rice plus two varieties of red and black rice. After rinsing the rice to remove excess surface starch, we placed 1 cup of each type with 1 cup of water in a vacuum bag and sealed them to ensure that no water could evaporate during cooking. We then submerged the bags in a 200-degree water bath until the grains turned tender—25 minutes for white rice types and 65 minutes for brown, red, and black rice types. After letting the cooked rice sit in the bags for 10 minutes, we emptied each into a separate bowl, fluffed the grains with a fork, and tasted for doneness. We repeated this test three times.
To the surprise of our tasting panel, every variety of rice was properly cooked using the 1:1 ratio of rice to water. All of the rice types were tender throughout with no chalky or mushy grains. In addition, the water had been completely absorbed in each sample.
Our findings support the claim that all rice cooks to the proper doneness with a 1:1 ratio of rice to water in the absence of evaporation. How does this translate to traditional rice cookery, where evaporation is always a factor? We have a better understanding of the purpose of published rice-cooking ratios. A cup of long-grain brown rice doesn't require more water than a cup of long-grain white rice, but it does need to cook for a significantly longer period of time in order for the water to work its way through the tough bran layer. That extended cooking time results in a greater amount of water lost to evaporation.
But there are other factors that influence evaporation, including the size and shape of the cooking vessel, how tightly the pot is covered, and the source and intensity of the heat. In addition, scaling ratios can be problematic because the amount of evaporation doesn't necessarily double when we double the quantity of rice. All of these variables demonstrate why set-in-stone ratios fail the home cook. The solution? Knowing your equipment and using a trusted recipe. We test our brown rice recipes extensively to determine the ideal amount of water for a given cooking setup. It is important to follow our instructions on pan size and oven or stove temperature, and to choose a properly fitting pan lid.
The Truth About Rice Ratios
We cooked 17 different types of rice, in vacuum- sealed bags to prevent evaporation, with a 1:1 ratio of rice to water. We were shocked to find that it worked for every type, including white, brown, red, and black rice. The problem for home cooks? You have to account for evaporation, pan size, and how tightly the lid fits on the pan.