Why remove some starch by rinsing?

Removing some starch by rinsing is done for a variety of reasons in cooking applications, including:

Preserving texture: Starch is a carbohydrate that is responsible for giving foods a certain texture and consistency. In certain dishes, such as sushi rice, it's important to remove some of the starch to achieve a desired texture. By rinsing the rice before cooking, some of the starch is washed away, resulting in individual grains of rice that remain separate and slightly sticky, giving the sushi its signature texture.

Preventing stickiness: Excess starch can cause foods to become sticky or gummy. Rinsing certain ingredients, such as pasta or noodles, before cooking helps remove some of the surface starch, preventing them from sticking together and allowing them to cook more evenly.

Reducing cloudiness: In soups, stews, or sauces, too much starch can make the liquid cloudy or murky. Rinsing ingredients like meat or vegetables before adding them to the cooking liquid can help reduce the amount of starch released, resulting in a clearer broth or sauce.

Enhancing flavor: Removing excess starch can sometimes lead to a more pronounced flavor of the main ingredients in a dish. By rinsing certain foods before cooking, some of the starch is removed, allowing other flavors to shine through.

Maintaining color: In some cases, excess starch can cause foods to discolor or darken during cooking. Rinsing ingredients like potatoes or vegetables can help preserve their natural color by removing some of the starch that could lead to discoloration.

It's important to note that the extent to which starch is removed depends on the specific ingredient, the desired outcome, and the recipe being followed. Some dishes may call for rinsing several times to remove as much starch as possible, while others may only require a brief rinsing to achieve the desired effect.