Demi-Glace

Traditional demi-glace (“half-glaze”) is brown stock that has been thickened with roux and reduced until it has the consistency of a light syrup. By the beginning of the twentieth century, demi-glace had become the standard sauce base (mother sauce) in professional kitchens and replaced many of the elaborate preparations that had been used up to that time. Nowadays, demi-glace is a simple reduction of stock, typically about fifteen times. Glace de viande is made in the same way except that it is reduced more, typically by about thirty times. When “concentrated stock” is called for here, it usually means four to six times.