yolk

OtherYear-round; commercial egg production is not seasonally dependent, though free-range eggs may show dietary variation based on seasonal feed availability.

Yolks are rich in choline, selenium, and lutein (important for eye health), and provide high-quality complete protein; they are also among the few naturally occurring food sources of vitamin D.

About

The yolk is the nutrient-dense center portion of a bird egg, consisting primarily of lipids, proteins, and lipoproteins suspended in a viscous emulsion. Egg yolks derive their characteristic golden to deep yellow color from carotenoid pigments—particularly xanthophyll—whose concentration varies with the bird's diet. Chemically, the yolk comprises approximately 50% water, 30% lipids (including cholesterol), 17% proteins, and smaller amounts of minerals and vitamins. The lipid composition includes both triglycerides and phospholipids (particularly lecithin), which confer crucial emulsifying properties exploited throughout culinary applications. Yolks from different poultry—chicken, duck, quail, and goose—offer varying fat and protein ratios, with duck and goose yolks containing notably higher lipid content.

Culinary Uses

Egg yolks function as multifaceted culinary components across virtually all cuisines. Their emulsifying capacity makes them indispensable for mayonnaise, hollandaise, béarnaise, and vinaigrettes; the lecithin naturally suspends oil droplets in aqueous media. As a binder and enrichment agent, yolks are essential to custards, ice creams, crème brûlée, and numerous baked goods, where they contribute structure and richness. Their coagulative properties when heated enable the preparation of scrambled eggs, soft-boiled preparations, and egg-based sauces. Yolks are also used as a glazing agent for pastries and breads to produce golden finishes.

Forms & Preparations

Whole liquid yolk — Fresh yolk separated from the white, used immediately or within 1-2 days; the standard form for most culinary applications.
Yolk powder — Pasteurized and spray-dried yolk; shelf-stable and used in commercial baking, mayonnaise production, and food manufacturing where fresh yolk is impractical.
Frozen yolk — Pasteurized yolk frozen in bulk; commercially used for extended storage and precise portioning in large-scale food production.
Cured yolk — Yolk salted, sugar-cured, or brined (as in Italian bottarga di tuorlo), then dried to create a concentrated umami ingredient for grating and garnishing.
Liquid egg yolk product — Pasteurized, stabilized yolk sold in food-service containers; maintains functional properties while reducing food safety risks associated with raw yolk.

Substitutes

Unknown — The liquid from cooked or canned legumes can emulsify in a 1:1 ratio for plant-based mayonnaise and meringues, though with less richness and different mouthfeel.
Unknown — Mix cornstarch with water to create a neutral binder for custards and sauces; use approximately 1 tablespoon per yolk, adjusting for desired consistency.
Unknown — Isolated soy or sunflower lecithin can replicate emulsifying properties in specific applications like vinaigrettes, though it lacks yolk's nutritional profile and richness.
Unknown — Direct substitutes with higher lipid content; use 1:1 by count, though they may yield richer, more intensely colored results.
Unknown — In some applications such as baking and glazing, whole egg can substitute for yolk at approximately 1 whole egg per 2-3 yolks, adjusting liquid ratios accordingly.