If you're like us, every time you hear about a kitchen hack—whether it's advice from grandma or trending on TikTok—you wonder: But does it actually work? In The Kitchen Scientist, we're asking author Nik Sharma (whose new book, The Flavor Equation, comes out in October!) to put it to the test.
It’s almost an unconscious act for most of us. Before we cook many ingredients, we inevitably make our way to the kitchen sink to wash them. This does a lot of things: It rids the food’s surface from grit, dirt, chemicals, and bugs. But in some instances, washing also helps improve the quality of a dish, especially when rice is involved.
I always wash my rice before soaking to get rid of all the unwanted things mentioned above—but also, more importantly, to get rid of any starch that’s present on the surface. That extra bit of starch will affect the outcome of whatever I’m cooking with that rice, be it a creamy rice pudding or pilaf.
Before we get into the whys and hows, let’s take a closer look at starch and rice.
Starch is one of the most common carbohydrates present in plants. It acts as a storage unit, made up of many units of glucose (a simple sugar/carbohydrate that is metabolized to produce energy). Every grain of rice contains granules of starch, plus a small amount of proteins and lipids.
Two types of starch are present in rice: amylose and amylopectin. Their quantities vary by the type of rice, which affects the final texture of the cooked grains. Varieties of rice with less amylose and more amylopectin, such as sticky rice, tend to be just that—stickier. Types like basmati, which contains a significantly larger percentage of amylose, but lower amounts of amylopectin, produce cooked rice that is less sticky and more firm.
Here’s a rough breakdown:
- Sticky rice (like Thai glutinous rice) contains nearly 0% amylose
- Short-grain or waxy rice (like arborio) contain 1% amylose
- Long-grain rice (like basmati and jasmine) contain at least 73% amylose
When rice is heated in water, the granules of starch inside the grain undergo physical and chemical changes, absorbing water and beginning to swell. The exact temperature at which starch begins to thicken varies quite a bit, depending on the plant and how the starch was processed (short-grain rice ranges from 131°F to 149°F; long-grain from 140°F to 176°F). Eventually, the chemical bond between amylose and amylopectin breaks.
Amylose, being a smaller molecule, easily escapes the granule, leaking out and forming a gel with the cooking water. Once the rice cools, the amylose crystallizes in a process called retrogradation (the same process responsible for this Genius Recipe telling you to overcook your pasta for pasta salad). The greater the amylose, the firmer and drier the cooled rice, which is why basmati appears firmer after cooking. Sticky rice, on the other hand, contains practically no amylose, so there is nothing to form a crystalline structure.
Compared to amylose, amylopectin is a very large molecule. When rice is cooked, this starch forms a very viscous liquid, increasing the overall stickiness. Unlike amylose, it lacks the tendency to retrograde. As a result, a short-grain rice variety like arborio, which contains a greater percentage of amylopectin, is ideal for risotto, where the cooking liquid becomes creamy, a result we love.
So, Why Wash Rice?
When you open up a container or bag of rice, those grains of rice have made quite the journey. During this time of processing, packing, travel, and storage, they constantly rub against each other. This friction between the dry grains of rice creates starch dust that coats the grains.
If the grains aren’t washed before cooking, this residual starch will gelatinize in the hot cooking water and make the cooked grains of rice stick to each other. In some instances, such as sticky rice varieties like glutinous rice and arborio rice, this can lead to a very gummy texture.
In the case of dishes like biryanis and pilafs/pulaos that use long-grain rice like basmati—and are judged in quality by how separate the cooked rice grains are—washing away the dust off becomes very important. The clarity of the runoff water indicates that most of the starch dust is rinsed away and the rice is ready to be soaked.
In kanji/congee, usually a short-grain rice, such as short-grain sushi rice (I even use arborio at times), is cooked in water or stock to form a thick, soupy liquid. While the starch dust might help thicken your soup, the rice should still be washed before cooking to remove any dirt, chemicals, and bugs that might be present. The innate properties of sticky rice (low percentage of amylose, higher amount of amylopectin) thicken the liquid with ease, so losing any of that starch dust during washing is not a concern. Also worth noting: Acids and excessive mechanical force can reduce the viscosity of amylopectin, so add any acidic ingredients, like lemon juice, at the end, and be gentle when whisking or stirring.
Some studies demonstrate that washing rice can significantly reduce the amount of heavy metals that accumulate in the plant (toxic heavy metals like lead, arsenic, and cadmium, if present in soil, can collect in plants). Some brands of rice are labeled as “enriched” and will come with a note to not rinse before cooking. This rice comes precleaned and is also enriched with various types of nutrients, like minerals and vitamins. I rarely buy this type of rice. The fortification of rice is done after the grains are dehusked and polished, and washing the rice in water takes away these nutrients. There is also another type of enrichment, in which genes are modified or introduced to improve the nutrient content of rice and even tackle health issues.
What About Soaking?
Soaking rice prior to cooking—usually 30 minutes is sufficient—provides a few benefits: First, it shortens cooking time as the grains absorb water. Soaking hydrates the grains and consequently the amylose and amylopectin inside the starch granules absorb water and swell. When it comes to types of rice that are noted for their fragrance, like basmati and jasmine, the aroma improves if the rice is soaked prior to cooking. This is because soaking, shortens the amount of time needed for cooking, resulting in a reduced loss of the aromatic substances (2-acetyl pyrroline) that naturally occurs during the cooking process.
Steps to Stellar Rice
When I prepare rice for cooking, be it long-grain or short-grain, I follow the same steps:
- Pick through the grains, removing any visible grit.
- Place the rice in a fine-mesh strainer of the appropriate size and rinse under cold running tap water, till the runoff is no longer cloudy. I prefer this method of washing rice because it gives a better visual endpoint to gauge when to stop (and the mesh prevents any grains from ending up in the kitchen sink). Note: Avoid rubbing the rice too much with your hands when rinsing—this creates more friction between the grains and you’ll be washing the rice forever as the run-off will continue to be cloudy.
- Soak the rice for 30 minutes in enough room temperature water to cover it by an inch. If you decide to soak the rice overnight, remember to watch the rice as it cooks, since your cooking time will decrease more significantly.
- Drain the soaking water.
- Cook the rice in a fresh batch of water or stock, as dictated by the recipe’s instructions.
How do you prepare rice at home? Do you rinse the grains before cooking? Do you soak the rice and for how long? And what type of rice do you use most often?