The demi-glace is a rich, sticky brown sauce that is the foundation of so many other sauces in French cuisine. It exemplifies the culinary alchemy of French technique that, over time and thorough attention to detail, transforms basic ingredients into rich, complex carriers of flavour.
Attributed to Auguste Escoffier, considered the father of French cuisine, the demi-glace base is an Espagnole sauce (or Spanish sauce), one of the French mother sauces. Espagnole is the French word for 'Spanish', but the French are fiercely protective of their cuisine and the sauce's origin story is controversial.
According to Louis Diat, the creator of vichyssoise and the author of the classic Gourmet's Basic French Cookbook: "There is a story that explains why the most important basic brown sauce in French cuisine is called sauce espagnole, or Spanish sauce. According to the story, the Spanish cooks of Louis XIII's bride, Anne, helped to prepare their wedding feast, and insisted upon improving the rich brown sauce of France with Spanish tomatoes. This new sauce was an instant success, and was gratefully named in honour of its creators.”
What is a demi-glace used for?
A demi-glace is a very rich, dark sauce and is therefore not really used as a sauce on its own, but as a base for other sauces. Adding red wine will give you a red wine sauce, exquisite with red meats. Adding mushrooms will give you a mushroom sauce, and so forth. A dollop of demi-glace will lift just about any stew or soup and because of its excellent covering qualities, a couple of spoons added to a ragu will make it wonderfully sticky.
For culinary students the demi-glace is gastronomy 101. It is a time-consuming process that requires no special ingredients apart from onions, celery, carrots, bones, beef, pork belly and pork. The basic idea is to combine one part Espagnole sauce with a brown stock, reduced by half and strained.
Ingredients for a demi-glace sauce
The ingredients are very basic and generally the only special thing you need to create a demi-glace is time and a little attention to detail. These are the basic ingredients for a homemade demi-glace:
2 tablespoons (or 1 ounce) clarified butter
1 Clove garlic
1 Bouquet garni
1/2 cup chopped yellow onions
1/4 cup chopped celery
1/4 cup chopped carrots
Veal or beef bones
Stewing or chuck steak
Kosher salt, to taste
How to make a demi-glace
There are many variations of the demi-glace. Some use a half chicken stock, and others use different techniques to speed up the process. However, for a classic demi-glace, there’s no way around it, you’re going to need time: about five or six hours at the very least.
For the Espagnole sauce
Melt the clarified butter in a large saucepan and add the mirepoix (onion, carrots and celery) and cook on a medium high heat until nicely caramelised. Add flour, an about equal amount to the butter, and cook. Stirring frequently to produce a brown roux.
Gradually add brown stock, preferably a brown stock, veal is best but a store-bought beef stock will work well if you don’t have time to make it yourself.
Add tomato paste and continue stirring constantly. Bring the sauce to the boil, add the bouquet garni and simmer for about an hour, long enough for the sauce to reduce.
Skim the surface of impurities and strain the sauce in a fine mesh strainer or cheesecloth. Set aside in the fridge for future use when cooled.
For the brown stock
Take your veal bones and place them in a roasting tin. Place the tin in the oven and roast on a medium heat for about 30 minutes, or until they give a deep brown colour. Turn the bones in the tin to make sure they brown on both sides.
Take the roasting tin out of the oven and sprinkle one diced carrot and one diced onion over them. Put back in the oven for another five minutes.
Transfer everything to a stock pot. Put the roasting tin back in the oven to really caramelise the remaining meat juices, and after a few minutes remove and deglaze the pan. Add the liquid to your stock pot.
Pour in enough water to barely cover the bones in the pot, add one clove of garlic and a bouquet garni and leave on the stove for a long time. Simmer stock for five or six hours minimum, it could be as much as 12 hours depending on the quantity of stock, checking there is always enough liquid.
When the bones are clean, strain the whole liquid in a strainer. This is your bone broth and you will now move on to make your actual brown sauce.
For the brown sauce
Take your pieces of fresh meat – veal shanks, chuck beef, pork belly and pork rind – and place in a pot with butter to brown.
When your pieces of meat are brown, ladle in the brown stock, enough to cover the meat. Bring to the boil and reduce it down. Repeat this process two more times.
When you have reduced the liquid to a glaze, you can then cover with the rest of the stock. This should then cook long enough for all the flavour to be extracted from the meat, about one or two hours. The liquid is then strained.
For the demi-glace
The demi-glace is a 50:50 combination of the above sauces, the Espagnole and the brown sauce, ladled into a pot and reduced by half (demi is French for half). You will finish with a very rich dark brown sauce that will keep for a long time in the fridge or indefinitely in the freezer.