thicken

Thicken is a verb describing the process by which a substance becomes more viscous, gel-like, or less runny, or the act of making it so. Thickenings alter flow properties by increasing solid content, reducing water mobility, or forming a molecular network that resists deformation. The outcome is often a change in texture, mouthfeel, and stability.

In cooking and food science, thickening is used to improve texture and consistency in sauces, soups, gravies, and fillings. Common methods include cooking to reduce liquid volume, which concentrates solids, and adding thickening agents such as starches (flour, cornstarch, arrowroot, tapioca), gums (xanthan, guar), or gelling agents (gelatin, pectin, agar). Heat can activate starches; acids, fats, or shear can influence results. Choice depends on desired clarity, temperature tolerance, flavor, and dietary restrictions.

Beyond food, thickening has uses in health care, medicine, and industry. Thickened liquids are prescribed for swallowing difficulties, prepared with commercial thickeners to achieve a safe consistency. In manufacturing, thickeners adjust viscosity in paints, inks, cosmetics, and personal care products. In mining and wastewater treatment, thickening processes promote settlement of solids before separation of liquids. In science, thickening relates to gel formation and viscoelastic behavior in polymers and colloids.