Nuts and Spices As Thickeners

Among seeds and other dry plant materials, only oily nuts can be made into a sauce base on their own. When such nuts are ground into “butters,” the oil provides the fluid continuous phase that lubricates the particles of cell walls and proteins. But most of the time, nuts are mixed with other ingredients, including liquids, so they become part of a complex suspension and help thicken both with their dry particles and with their oil, which becomes emulsified into tiny droplets. Almonds have long served this purpose in the Middle East and Mediterranean in such sauces as romesco (with red peppers, tomatoes, and olive oil) and picada (garlic, parsley, oil), and the coconut in tropical Asia, where it’s pounded along with spices and herbs to become part of the sauce for cooked meats, fish, and vegetables.