homemade brown stock. I find homemade stocks to be superior to store-bought canned stocks, but they are labor intensive. If you just haven't had enough fun while making your own stock, and are a complete glutton for punishment, you can reduce your stock to create two other flavor vehicles and enhancers: demi-glace and glace de viande.
When making stocks, I don't normally reduce them. Very few recipes require it. Their are a few advantages, though. Stock reductions have more concentrated flavor, take up less storage space, and can be stored for a much longer time. This makes them a wonderful solution for long-term food storage.
Just to remind you, the last step of making the brown stock was to reduce the stock down to about 3 quarts of liquid. You may also recall that I don't normally do this. I find that I can just freeze the stock at this point and it's just fine. To make the demi-glace and glace de viande, however, you should reduce the stock to about 3 quarts before proceeding.
You'll be much happier if you heed my earlier warnings and don't add any salt when making your stock. The salt concentration will be way too high when it gets reduced, otherwise.
Making a Demi-glace
A demi-glace is used as a base for sauce espangole, one of the five French “mother sauces” as codified by French chef Auguste Escoffier. It can be used as a base for other sauces as well, or used on it's own. Because it is labor intensive to make, many cooks will substitute it with a simple jus lié.
To make a demi-glace, reduce the stock by half (again), and cool. A cooled demi-glace will solidify into a gelatin-like substance that can be cut into large chunks, wrapped in plastic and frozen. In the regrigerator, a demi-glace will keep for about six months. In the freezer, it will keep almost indefinitely.
Sometimes, the demi-glace will be gelatinous, but not completely solidify. In that case it should be frozen in a plastic zipper lock bag or other plastic freezer container, much like a regular stock.
Making Glace de Viande
Glace de viande, or “meat glaze,” is a dark brown, gelatinous, flavoring agent bordering on bouillon. I use it much the same way as bouillon, using it to flavor soups and sauces.
To make glace de viande, strain the hot (and still liquid) demi-glace again and reduce over medium low heat to it's maximum. As it reduces, you can transfer the liquid to a smaller, more sturdy, saucepan. The last hour or so of reduction should be done over very low heat. All of the free water is being removed and it can burn if you're not careful. The glace will get very dark and thick, like molasses. Bubbles will form on top like they do with caramel. You'll know you're nearing the last 15 to 20 minutes when the bubbles break, but no steam escapes. If there is any fat left in the mixture, it will separate and should be removed with a spoon.
The mixture is fully reduced at this point and will be as thick as caramel. Remove the glace de viande from the saucepan to a clean bowl to cool. Use a spatula to scrape as much off the sides of the saucepan as you can.
A cooled glace de viande will become a rubbery solid that can be stored in a loose jar or open bag in the refrigerator almost indefinitely. You don't really need to freeze it, although you can.
There will be a lot of glace left over in your pan. In order to recover it, and clean your utensils, place the spoon and spatula back in the saucepan and fill it with water. Bring it to a boil, remelting the glace. The sticky stuff should now be off the utensils, making them easier to clean, and the liquid can be used as stock.
Making stock, demi-glace, and glace de viande are pretty labor intensive, as you can see. I think the results are worth it, though. I certainly wouldn't want to make it very often. That's just too much, even for me. Once or twice a year, though, will improve your sauces and add to your food storage skills.
Photo credit: Silvia McCabe