What eggs do in baking
Intermediate Kitchen science
Eggs build structure, trap air, bind fat and water together, and add richness and color, depending on how you use the whites and yolks.
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How do you do it?
- Use large eggs unless told otherwise; one large egg is about 1.75 ounces (50 grams) out of the shell.
- Add extra yolks for richer, more tender custards and cakes; add extra whites for a lighter, drier, sturdier crumb.
- Beat eggs in one at a time so each blends fully into creamed butter without curdling.
- Warm eggs in warm tap water for 5-10 minutes before using; cold eggs can firm up creamed butter and curdle the batter.
Why does it work?
Egg proteins unfold and set as they heat, forming a mesh that holds a cake or custard in shape. Beaten whites trap air in a foam that expands in the oven, so eggs also leaven, and the water in them turns to steam for extra lift. Yolks contain lecithin and other emulsifiers that hold fat and water together for a smooth batter, plus fat that tenderizes. The proteins and sugars in eggs brown well, which is why egg wash makes crusts golden. Whites dry and firm; yolks enrich and soften.
What are the common mistakes?
- Swapping egg sizes freely — too much or too little liquid and structure.
- Adding cold eggs all at once — batter curdles and bakes up coarse.
Still stuck? Watch someone do it on YouTube.
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