When it goes wrong · Emulsify
It formed, then broke a few minutes later.
Can you save it?
Reviewed for this symptom
Whisk a spoonful of cold water into it off the heat; if it does not come back, start a fresh yolk in a clean bowl and whisk the broken sauce in gradually. Keep it warm, not hot, once rebuilt.
How to confirm the diagnosis
Observable cues, not inferred user state
- It was smooth, then loosened and separated
- It sat on or near direct heat
- The bowl or pan was hot to the touch
Not this?
- The sauce separates into an oily layer and a watery one.
- It never thickened at all and stayed thin and clear.
- Grainy rather than split — visible curds.
What actually happened
Only this symptom
Temperature. Heat thins the fat and speeds droplets into each other; in a yolk-based sauce, heat also cooks the emulsifier out of existence.
The full mechanism
Shared by every emulsify failure
Fat and water do not dissolve in each other, so left alone they separate into two layers — the arrangement with the least contact between them. An emulsion suspends one inside the other as droplets, and it needs two things at once: mechanical energy to tear the droplets small, and an emulsifier to coat each droplet so it cannot merge back. Emulsifiers are molecules with a water-loving end and a fat-loving end — lecithin from egg yolk, casein from butter and cream, the mucilage in mustard, dissolved starch from pasta water. Whisking without an emulsifier gives you a mixture that separates within a minute. Adding fat faster than the whisk can break it leaves droplets uncoated, they coalesce, and the sauce splits.
The full Emulsify lesson — how to tell, where to practise it, what it carries to.
Next time
Prevent this specific failure
Hold finished sauces warm, off direct heat, over a bowl of warm water, and serve within the half hour.
What right looks like
Shared by every emulsify failure
- The mixture turns opaque. Two separate layers are translucent; an emulsion scatters light and goes pale and matte.
- It thickens noticeably even though nothing was added that thickens — the resistance comes from packed droplets.
- It coats the whisk or the back of a spoon and holds a line drawn through it.
- The sound changes as it forms, from a thin slosh to a heavier, quieter sound.