Process Frees Starch

• Masa harina makes a good thickener for soups, stews and chili because the process that creates it changes both its physical and chemical structures. The corn soaks in boiling water with lime, then the hulls are removed from the kernels. The kernels soak in a combination of water and wood ash until they puff up to make what's called hominy. The process, known chemically as nixtamalization, breaks down a glue-like component called hemicellulose and frees up starch, which is what makes liquids thicken in cooking.

Make a Masa Paste

• To thicken stew, soup or chili, add water to 2 to 3 tablespoons of masa harina to make a thick paste. Mix the masa harina with water before adding it to the stew to help avoid lumps. Add enough water to the paste so it's easily stirred, and mix until the paste is completely smooth. Don't add too much water, though; the consistency of a masa harina mix should be thicker than the slurry made when mixing flour or cornstarch with water to make a thickener. Add the masa paste to the stew and stir constantly until the liquid thickens, which should happen within minutes.

Sweet Corn Flavor

• How much masa harina to use for thickening will depend on how thick you want your stew and how much corn flavor you want. Although masa harina is typically a fine-milled powder, it has a detectable sweet corn taste as part of a soup, stew or chili. Its sweetness makes it a tasty complement to chiles such as savory poblano and spicy jalapeno, and to tart tomatillos. Unless your diners are inordinately fond of corn, however, reduce or eliminate other types of corn from the ingredients in your soup or stew when using masa harina as a thickener.

Store Dry or Frozen

• Well-wrapped or kept in a glass jar with a tight-fitting lid, masa harina will keep at room temperature in a dry place for up to a year. Masa harina also freezes well, but it should come to room temperature before you add it to a recipe.