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Lesson
Lesson 2. How not to break a sauce (and how to save it)
Understand why an emulsion separates, how to prevent it, and how to “fix” a broken mayonnaise or sauce.
Why a sauce “breaks” and how to bring it back
Rescuing a broken mayonnaise
An emulsion is delicate. The oil droplets always “want” to merge back together, and there are a few typical reasons it happens.
First and foremost: the oil went in too fast. The emulsifier can't coat all the new droplets, and the mix splits into fat and liquid. So add oil drop by drop, then in a thin stream, whisking constantly; speed up once the emulsion has come together.
Second, too little watery base: the droplets need some water or lemon juice to hang in; in nearly pure oil they clump.
Third, a sharp temperature gap (ice-cold yolk, warm oil) or overheating, as with hollandaise: the yolk curdles into lumps.
Now the rescue. A broken mayonnaise can almost always be brought back. Take a clean bowl and put in a new emulsifier base: a fresh egg yolk (or a spoonful of prepared mustard, or a spoonful of mayonnaise that worked). Then, whisking, gradually pour the broken mixture into that base in a thin stream. You're essentially rebuilding the emulsion, giving the emulsifier a chance to coat the droplets properly. Most of the time the sauce becomes thick and smooth again.
The principle: an emulsion is ruined by haste and too little emulsifier or water, and fixed by patiently pouring it again into a fresh base.
Lesson notes
Rescuing a broken mayonnaise
An emulsion is delicate. The oil droplets always “want” to merge back together, and there are a few typical reasons it happens.
First and foremost: the oil went in too fast. The emulsifier can't coat all the new droplets, and the mix splits into fat and liquid. So add oil drop by drop, then in a thin stream, whisking constantly; speed up once the emulsion has come together.
Second, too little watery base: the droplets need some water or lemon juice to hang in; in nearly pure oil they clump.
Third, a sharp temperature gap (ice-cold yolk, warm oil) or overheating, as with hollandaise: the yolk curdles into lumps.
Now the rescue. A broken mayonnaise can almost always be brought back. Take a clean bowl and put in a new emulsifier base: a fresh egg yolk (or a spoonful of prepared mustard, or a spoonful of mayonnaise that worked). Then, whisking, gradually pour the broken mixture into that base in a thin stream. You're essentially rebuilding the emulsion, giving the emulsifier a chance to coat the droplets properly. Most of the time the sauce becomes thick and smooth again.
The principle: an emulsion is ruined by haste and too little emulsifier or water, and fixed by patiently pouring it again into a fresh base.