An Actual Post About Sauce

Saucyman, what is the difference between demi-glaze (glace) and a reduction?

Demi-glace, viande-glace or veau-glace all have traditional meanings that were defined by master kitchen taxonomist, Escoffier. Demi-glace, in particular, had the distinction of being a mother sauce, one of 4 sauces in the classic kitchen that smaller sauces could be made quickly from. Demi-glace is the mother of all brown sauces – old school (Victorian Era not ’92) sauces like the Sauces Robert, Duxelles, Bordelaise are all derivatives of demi-glace. These recipes like Escoffier himself, the type of kitchens he managed and the cuisine he prepared - are all dead. In the modern food world demi-glace and reductions are used interchangeably without too much confusion.

The term demi–glace is a bit of a misnomer. Demi, which literally means half, here denotes a sauce reduced by at least 2/3 of its original volume. Glace translates as ice -why ice for a sauce that is made by boiling stock for hours before the serving hot? I don’t know why, they’re French. Despite using two inexact words in its name, a demi-glace does have some specific attributes: First a demi-glace connotes that the sauce is based on beef or veal bones. In cookbooks and on menus demis are duck, lamb, quail, chicken and yes, even tomato. More importantly, calling a sauce a demi-glace implies it contains a thickening agent like the fat and flour combo called roux.

Whether it is actually a roux that is doing the thickening or arrowroot, pureed rice, cornstartch or tapioca - thickening agents do two things – save time and time’s corollary, money. Getting a gallon of beef stock down to 2 cups of reduction takes some serious time - 6 to 10 hours from making the stock to the final reduction. Adding a thickening agent adds color, means the sauce doesn’t have to be reduced as much and means the final product doesn’t have to rely solely on the gelatin extracted from the bones to thicken the demi-glace.

A reduction is straight-up honest concentration of ingredients. Usually a cook boils bones, then adds aromatics – onion, carrot, leek, celery, laurel, thyme, parsley - eventually the solids are removed, after a certain point in the preparation, all the flavor has been extracted. This liquid keeps getting boiled away until the saucepan contains a stock that is about the consistency of maple syrup. A reduction can be anything – wine, balsamic vinegar, vegetable, fish, fowl or meat.

So how is it that two words that have separate identities are used interchangeably? Arguably it is because restaurant kitchens are not professional environments – it is a place where people use pork as a verb and this is despite the fact they should know better because they are offering pork the noun on the menu. That and certain words and terms add value to a meal. While not everyone knows the dictionary definition, demi-glace might ring a bell to a casual diner – a word faintly remembered from watching Martha or Emeril. Possibly a word they have never heard from the lips of Rachel Ray – ergo it is something that takes more time than 30 minutes to make and therefore good.