A piquant compound brown sauce built on a reduction of white wine, white wine vinegar, shallots, cayenne, and black pepper — deglazed with demi-glace and finished without straining (the shallot fragments are integral to the sauce's texture and appearance). Sauce diable is the sauce of grilled preparations, of devilled chicken (poulet à la diable), and of any preparation that requires a sauce with heat, acid, and depth simultaneously.
- Reduction: white wine + white wine vinegar + finely minced shallots + cracked black pepper + thyme, reduced to nearly dry. - Add demi-glace. Simmer 10 minutes. Do not strain — the shallot and pepper are visible in the sauce. - Season with cayenne to the correct heat level — assertive but not dominant. - No butter mounting for the diable — it is served slightly thinner and more austere than the butter-mounted sauces. Decisive moment: The vinegar reduction. The vinegar's volatile acetic acid compounds are largely driven off during the first reduction — what remains is a concentrated, slightly sharp base that tempers the demi-glace's richness. Too little reduction: the sauce tastes of raw vinegar. Too much: the vinegar's character disappears entirely and the sauce becomes another brown sauce without the diable's defining sharpness.
Jacques Pépin's Complete Techniques