Dried egg whites

One US cup of dried egg whites weighs between 80 and 107 grams (2.8 to 3.8 ounces), depending on how the cup is filled and which source measured it. Use 88 grams (3.1 ounces) as a middle figure, or weigh 4 to 5 g of powder per egg white replaced. Every figure behind it is below, with the method each source used.

Also called egg white powder, powdered egg whites, dried egg white powder, albumen powder, dehydrated egg whites.

A cup of dried egg whites weighs 80 to 107 g (2.8 to 3.8 oz). Judee's label gives 5 g per tablespoon (80 g per cup), King Arthur 11 g per 2 tablespoons (88 g), Deb El's Just Whites 4 g per 2 teaspoons (96 g) and USDA 107 g for a sifted cup. The powder is light and fluffy, so spoon measures are unreliable; weigh it, using 4 to 5 g of powder for each egg white.

Dried egg white, sold as egg white powder, powdered egg whites or albumen powder, is pasteurized liquid egg white with its trace of natural glucose removed, so it does not brown in storage, then spray-dried to a fine powder. USDA's Standard Reference record (FDC 170895, egg white, dried, stabilized, glucose reduced) lists 5.5% water and 84% protein. Bakers use it for meringues, macarons and royal icing without raw-egg concerns, and to add whites without separating eggs. It is not meringue powder, which blends egg white with sugar, starch and stabilizers.

The figures span 34%, beyond the 10% this site allows for powders, so the entry publishes the range. Most of the spread is rounding. Labels state whole grams on small spoons: 4 g for 2 teaspoons could be anything from 3.5 to 4.5 g, 84 to 108 g per cup, and 5 g per tablespoon covers 72 to 88 g. USDA's 107 g is for a sifted cup, which for most powders is the lightest way to fill one; that it is the heaviest figure here suggests a denser, more granular powder than today's retail brands. King Arthur's 88 g sits inside the range and is accepted.

The physical check comes from the egg itself. A large fresh egg white weighs 30 to 35 g (King Arthur's chart) and is about 88% water, so it holds about 4 g of dry solids. Judee's says its 8 oz bag equals 45 egg whites, 5 g each. Just Whites' package directions use 2 level teaspoons of powder with 2 tablespoons of warm water per white, about 4 g at its labelled weight. Both match the 4 g of solids in a real white, and 2 tablespoons of water, about 30 g, replaces the water. Dry egg protein has a density of about 1.3 g/mL, so a cup at 80 to 107 g is only a quarter to a third solid and the rest air, typical of a fine, cohesive spray-dried powder, which is why a spoonful varies so much.

Practical guidance: weigh the powder by the number of whites it replaces, 4 to 5 g each, and reconstitute it with about 2 tablespoons of water per white. By volume, a level tablespoon holds 5 to 7 g; use 88 g per cup as a middle figure. Whisking the powder into the recipe's sugar before adding water helps it dissolve without lumps. For macarons and meringues, where a few grams of protein change the result, a scale is the only reliable measure.