The encyclopaedia of gravy
Demi-glace is a rich, glossy French brown sauce made by reducing brown stock, traditionally with espagnole sauce. It is more concentrated and technically defined than ordinary gravy, and is used as a base for finished sauces.
Demi-glace is a concentrated brown sauce of classical French cuisine, made by reducing brown stock with espagnole sauce until glossy, rich and intensely savoury. The name means “half-glaze”, referring either to the traditional equal mixture of espagnole and brown stock, reduced by half, or to the half-glazed appearance of the finished sauce.
It is related to jus and beef gravy, but is not simply an elaborate name for either. Demi-glace is a prepared sauce base, generally strained to a smooth consistency and used in small quantities to build other sauces. Ordinary gravy is usually served directly with a meal and may contain roasting juices, flour, onions or other ingredients that would be out of place in a classical demi-glace.
Classical definition¶
The version codified in the French culinary tradition combines equal quantities of espagnole sauce and brown stock. This mixture is simmered and reduced until its original volume is roughly halved, then strained. The result should coat the back of a spoon, possess a dark brown colour and have a concentrated but balanced flavour rather than the taste of burnt stock.
Espagnole is one of the classical French mother sauces. It is made from brown stock thickened with a brown roux and enriched with browned vegetables and tomato. In the traditional method, the espagnole is therefore not merely a flavouring but part of the sauce's structure. The stock supplies gelatin and roasted meat flavour; the espagnole supplies body, colour and additional cooked aromatics.
Modern professional kitchens often use “demi-glace” more loosely for a highly reduced brown stock, particularly when the stock is already well made and naturally gelatinous. This is practical, but it is not identical to the older formula.
Ingredients and proportions¶
| Component | Classical choice | Purpose |
|---|---|---|
| Brown stock | Beef or veal, sometimes mixed | Meat flavour and gelatin |
| Espagnole | Equal volume to the stock | Body, colour and aromatic depth |
| Mirepoix | Onion, carrot and celery | Background sweetness and savouriness |
| Tomato | Tomato purée in the espagnole | Colour and acidity |
| Wine | Optional, depending on the sauce | Deglazing and balance |
| Seasoning | Usually added to the finished sauce | Prevents over-salting during reduction |
Veal stock is prized because it gives a clean flavour and abundant gelatin, while beef stock produces a darker and more assertive sauce. A stock made with beef stock or gelatin from bones can produce a convincing modern version, provided it is well skimmed and not heavily salted.
Salt requires particular care. A liquid reduced to one quarter of its original volume can become unpleasantly salty even when it tasted correctly seasoned at the beginning. The safest practice is to reduce the stock and sauce without salt, then season the finished demi-glace.
Traditional method¶
A classical preparation begins with a well-made brown stock. Bones are roasted at about 220°C until deeply browned, usually for 45–60 minutes, while the vegetables are browned separately or added towards the end. The bones are then simmered gently with water and aromatics for several hours. Vigorous boiling makes the stock cloudy and can emulsify fat into the liquid; straining and skimming gravy describes the same problem in a less formal setting.
The espagnole is prepared separately with a brown roux, browned mirepoix, tomato and brown stock. Once both components are ready, equal quantities are combined in a wide pan and brought to a very gentle simmer. The sauce is reduced by approximately half, commonly over 60–90 minutes depending on the quantity, pan shape and heat.
The sauce is passed through a fine sieve or chinois, then reduced further if necessary. It should be thick enough to cling to a spoon but still flow readily when warm. A properly made demi-glace does not need cornflour, gelatine powder or gravy browning. Its body comes from reduction and naturally occurring collagen, not from a last-minute starch slurry.
⚠️ Do not reduce it unattended
A demi-glace can pass from concentrated to scorched with surprising speed. Use a heavy pan, maintain a bare simmer and scrape the base occasionally with a wooden spatula.
The modern shortcut¶
A practical home method starts with 1 litre of unsalted brown stock and reduces it slowly to about 250–300 ml. For a closer approximation to the classical sauce, whisk in 250 ml of prepared espagnole before the final reduction, or add a small amount of brown roux and tomato purée at the beginning.
A faster version uses good-quality commercial stock, roasted meat trimmings and a pressure cooker. The stock can be reduced after pressure cooking, when evaporation is easier to control. Commercial demi-glace concentrates and powders also exist, although their salt, yeast extract and thickener content varies considerably. They are ingredients rather than exact substitutes for a long-reduced sauce.
The finished sauce should be cooled quickly in a shallow container, refrigerated and used within three days, or frozen in small portions. Ice-cube trays are useful because demi-glace is normally added by the spoonful rather than served in a ladle. It sets firmly when cold because of the gelatin, then becomes fluid again when gently reheated.
Uses in cooking¶
Demi-glace is rarely poured over a plate in the quantities associated with British roast gravy. It is used as a foundation for finished sauces, often loosened with wine, stock, cream or fortified wine.
Common derivatives include mushroom sauce, pepper sauce, Madeira sauce and red-wine sauce. A spoonful can enrich pan gravy made from steak juices, or deepen a sauce for roast beef, game, lamb or duck. It also gives body to braising liquids and can be whisked into a reduction made from red wine in gravy.
The sauce must be matched to the food. A strongly reduced beef demi-glace can overwhelm delicate chicken or vegetables, while a veal-based version is more adaptable. For vegetarian cooking, a reduction of roasted mushrooms, onions and vegetable stock can provide similar concentration, though it is not demi-glace in the classical sense; vegetarian gravy is the more accurate description.
Demi-glace and gravy¶
The two sauces overlap in purpose but differ in convention. Gravy is a broad category of savoury sauce, often made from the juices and fat left after roasting meat. Demi-glace is a specific French preparation whose identity depends on brown stock, reduction and a smooth, concentrated finish.
A roasting tin sauce may contain flour, onion fragments, herbs and the browned sediment known as fond. Demi-glace is normally strained and refined until none of these elements remains visible. Nor does it require a roast to have taken place that day: the stock and sauce can be prepared well in advance.
The distinction is not always maintained on menus or product labels. “Demi-glace” may describe anything from a classical sauce to a packet mix with starch and flavourings. The name, like many culinary terms, has acquired a wider working meaning than its original recipe. The pan is not obliged to conduct a linguistic inquiry, but the cook should know which version is being made.