Overview

Fats and oils are a broad class of lipids composed primarily of triglycerides: triesters of glycerol bonded to three fatty acid chains. They are soluble in organic solvents and largely insoluble in water. At room temperature, fats are typically solid and oils are liquid, a distinction driven by the degree of saturation of their constituent fatty acids.

Origin and history

Fats and oils have been extracted and used by humans for thousands of years, with evidence of olive oil production in the Mediterranean dating to at least 2500 BCE [1]. Animal fats such as lard and tallow were rendered and used for cooking, lighting, and soap-making across Europe, Asia, and the Americas. The industrial revolution introduced mechanical pressing and solvent extraction, dramatically increasing the availability of vegetable oils from seeds like cottonseed, soybean, and palm [1]. Hydrogenation, developed in the early 20th century, allowed liquid oils to be converted into semi-solid fats, enabling the mass production of margarine and shortening [2].

Varieties and aliases

  • Animal fats: lard (pork fat), tallow (beef or mutton fat), schmaltz (chicken or goose fat), butter (milk fat)
  • Vegetable oils: olive oil, coconut oil, palm oil, soybean oil, canola oil, sunflower oil, sesame oil, peanut oil, avocado oil
  • Tropical fats: coconut oil, palm oil, palm kernel oil (high in saturated fats, solid at room temperature)
  • Processed fats: shortening, margarine, ghee (clarified butter), hydrogenated oils

Culinary uses

Fats and oils serve as cooking mediums for frying, sautéing, and roasting, and as structural ingredients in baked goods, where they contribute tenderness, flakiness, and moisture. They are used to make emulsions such as mayonnaise, vinaigrettes, and hollandaise. In confectionery, cocoa butter and other fats provide mouthfeel and snap. Fats also carry fat-soluble flavors and aromas, making them essential for infusions and dressings. Smoke point varies widely by fat type and refinement level, dictating appropriate cooking methods [1].

Cross-cuisine context

Fats and oils are universal across cuisines, but specific fats define culinary traditions. In Mexican cuisine, lard (manteca) is traditional for refried beans, tamales, and flour tortillas, while vegetable shortening is a common modern substitute. Olive oil anchors Mediterranean cooking; coconut oil and ghee are central to South Indian and Southeast Asian cuisines; sesame oil is foundational in Korean, Chinese, and Japanese cooking. In LA’s Salvadoran and Guatemalan communities, manteca is used for pupusas and refried beans, mirroring Mexican usage. Persian cuisine relies on butter and ghee (roghan) for rice dishes and stews. No direct analogue exists across all cuisines because each tradition selects fats based on available livestock, crops, and religious or dietary restrictions.

Notes for cooks

  • Smoke point determines suitability: use refined avocado or grapeseed oil for high-heat searing, extra-virgin olive oil for low-heat or raw applications.
  • Rancidity is signaled by off odors (painty, fishy, or metallic) and can be slowed by storing fats in cool, dark, airtight containers.
  • Substituting fats in baking changes texture: butter adds water and milk solids, while oil produces a more tender crumb; lard yields flaky pastry.