Slurries are an essential tool for creating perfectly smooth and velvety soups and sauces. But.. what is a slurry?
A slurry is a thickener consisting of a pure starch mixed with a cold liquid to form a thin paste or “slurry.” Cornstarch is used most often, but others such as arrowroot or potato starch are also commonly used. Combining the starch with a cold liquid before adding it to a hot liquid (such as a sauce, like in this Spicy Tofu with Mushrooms) allows it to mix in thoroughly. A starch that is added directly to a hot liquid will clump together and ruin the texture of the sauce and will not act to thicken. By first creating the slurry, the starch can be more evenly mixed into the hot liquid it is thickening and the result will be velvety smooth.
To make a slurry, thoroughly blend the starch and liquid until it is about the consistency of heavy cream. Slurries can be blended in advance and held to use during last minute preparations. If not used immediately, the starch will settle out of the liquid and fall to the bottom of the container. Stir the slurry just before use to recombine the starch evenly with the liquid.
Pour or ladle the slurry into the simmering liquid while stirring constantly. When added in this way, slurries quickly thicken the liquid, making it easy for you to control the final consistency of the dish. Whisk constantly to prevent lumps and scorching. Bring the liquid back to a boil and cook just until the sauce reaches the desired thickness and clarity.
There are no firm rules or ratios to determine how much slurry you need for your use. To start, combine 1 tablespoon of starch with 2 tablespoons water or other cold liquid. Add a little at a time, allowing the mixture to come to a boil before adding more. Make more slurry, as needed.
