Demi is that rich, velvety sauce you'll find in one form or another on a number of my plates. Known as a "mother" sauce it can be morphed into hundreds of other sauces. It's a central component in my kitchen. I was taught how to make it over 20 years ago by my French trained mentor Claus Bienek. It's the same method that's been used for centuries. Some chef's may have their own take on it but essentially it's universal. Making it is a long arduous process. This is how I do it.
(The plate above has a foie gras infused demi-glace.)
Start with veal bones. These are nice meaty neck bones. It's going to be a good batch. Like the grape is to fine wine so are the bones to demi. I very lightly salt and pepper them before roasting. I think it draws liquid to the service and helps in caramelization.
I use a big "stock pot" to saute onions, garlic, celery, carrots, parsley and whatever is getting too ripe. (With exceptions.) Here I had some extra squash and fresh side straps from tenderloins. After a thorough saute I reduce a liberal amount of red wine over the vegetables.
Your bones are ready when they have a nice even caramelization. Add them to the stock pot.
De-glaze the roasting pan. Scraping all the stuck on pieces loose and pour in the stock pot.
Cover with cold water add bay leaves, black peppercorns, tarragon and bring to a boil. Skim scum and simmer. Now forget about it for 24 hours.
Strain and reduce.
First taste. Kind of like a wine maker barrel tasting. I'll adjust the flavor if needed and determine how much to reduce it. After I'm satisfied with the flavor I'll reserve a portion and reduce that further to glace de viande. The intense, sticky, rich royal cousin to demi. I'll thicken the demi ever so slightly with a roux enrich with a little whole butter and strain through a "chinoise", a very fine sieve.
From stock pot to demi. I'll reduce the demi a little further for each day's service.
