glace. This simple reduction of a well-made stock yields one of the most powerful ingredients in the kitchen. The only way to describe the taste is to call it the most highly concentrated essence of savory. It’s a natural flavor enhancer and a little bit goes a long way.
Turning stock into demi-glace is fairly easy, but it does take time, patient observation, and skimming. At the restaurant, I like to call it babysitting. No one needs to stand there and watch the pot while it is reducing, but it is important to glance over and skim it every 10 to 15 minutes.
We make two batches of demi-glace a week at Beast, using 100 pounds of bones each time, because we serve it on so many things. A modest drizzle of warm demi-glace instantly heightens the flavor of any piece of meat, and once you have tasted it, you’ll want to put it on just about everything, too.
- 4 quarts homemade stock
- In a pot, bring the stock to a gentle boil (or rolling simmer). The bubbles shouldn’t be violent or hard; instead, the stock should look like it is rolling into itself over and over, like a swiftly moving river. Once that rolling motion has started, skim the stock every 10 to 15 minutes. The best way to do this is to keep a small (4- to 6-ounce) ladle near the stove—something that you leave in a visible place to remind you to skim continually. To ladle off the scum, fat, and proteins that gather, tilt the ladle at a 45-degree angle near the fat, pressing ever so slightly into the liquid and allowing the fats to “swim” into the ladle. It’s important to skim slowly and carefully to avoid getting any of the precious stock into the fat mix that you will be discarding.
- After 1 hour, if you have been diligently skimming, the stock should release fewer particles and less fat, so you can skim slightly less often. After about 1½ hours, the liquid should be much darker and starting to thicken. At this point, the stock should have reduced significantly, to about 1 quart. Transfer the liquid to a small 2-quart saucepan. Turn the heat down as low as possible (what a shame it would be to burn your liquid this close to the end!) and stir occasionally until the liquid is the consistency of a thin maple syrup and has reduced to about 1 cup, about 1 hour and 50 minutes more. Check the stock frequently to ensure you don’t reduce it too much.
- To test if the demi-glace is ready, spoon about ½ teaspoon onto a small plate. It should still be liquid, but when you drag your index finger through it, your finger should leave a trail. The demi-glace should not be sticky, and it should have a smooth mouthfeel and very rich taste. If you have accidentally reduced it too much, you can add 1 to 2 tablespoons of water or a little red wine reduction.
- Store in an airtight container in the refrigerator for up to 1 week or in the freezer for up to 3 months.