How to make homemade stock concentrates (glace or demi-glace) for sauces
Making your own stock concentrates like glace or demi-glace gives sauces deep, complex flavor and lets you control salt and quality. With patience and a few simple techniques you can reduce store-bought or homemade stocks into intensely flavored glues that keep for months. Follow these practical steps to make concentrated stocks that enrich pan sauces, braises, and soups.
Step 1: Choose base stock and bones
Start with 6–12 cups of good stock — homemade is best, or use low-sodium store-bought. For meat glacé or demi-glace, roast 2–3 pounds of bones and vegetables at 425°F for 35–45 minutes first to deepen flavor, then simmer with 2–3 cups water per pound of bones to make a rich stock. Strong starting flavor yields a better concentrate.
[Illustration: Roasted bones and vegetables on a baking sheet next to a large pot of simmering stock]
Step 2: Clarify if needed
If your stock is cloudy, clarify with egg whites: whisk 3–4 egg whites per 2 quarts of stock and simmer gently while the raft forms and collects solids for 15–20 minutes, then strain. Clarified stock reduces sediment and produces a glossy, clean-flavored concentrate that reduces evenly.
[Illustration: Straining a pot through cheesecloth with a pale raft of egg whites on top of simmering stock]
Step 3: Reduce gently and uncovered
Simmer stock uncovered over medium-low heat to maintain a slow, steady simmer; reduce 4–10 times depending on desired concentration. For glace, reduce to a thick jam-like consistency (about 1–1.5 cups from 6–8 cups) over 3–6 hours; for demi-glace, reduce by roughly half to one-third over 2–4 hours. Slow reduction preserves flavors without burning.
[Illustration: Large wide saucepan gently simmering with steam rising and a measuring cup showing reduced volume]
Step 4: Skim and degrease regularly
Every 10–15 minutes, skim foam and fat from the surface with a ladle; after most fat is removed, chill and remove remaining solidified fat or use a fat separator. Removing excess fat prevents rancidity and helps the final concentrate set with a clean texture and intense taste.
[Illustration: Ladle skimming foam from the surface of simmering stock with a bowl of separated fat beside it]
Step 5: Finish with final reduction and seasoning
Once reduced to the target volume and viscosity, simmer the last 30 minutes to concentrate taste, then taste and season sparingly — concentrated stocks are very salty, so add no more than 1/4–1/2 teaspoon salt per cup if needed. For demi-glace finished with wine, add 1 cup red wine earlier and reduce with the stock so flavors meld.
[Illustration: Thick glossy dark concentrate being tasted from a spoon with a small salt shaker nearby]
Step 6: Strain and cool quickly
Strain the concentrate through a fine-mesh sieve lined with cheesecloth into shallow pans to cool quickly and remove any remaining solids. Cool at room temperature for 20–30 minutes then refrigerate uncovered until firm, which helps fat rise and makes portioning easier.
[Illustration: Pouring deep brown concentrate through cheesecloth-lined sieve into shallow metal tray]
Step 7: Portion and store properly
Spoon or cut chilled concentrate into 1–2 tablespoon portions and freeze on a tray for 1–2 hours before transferring to labeled freezer bags or jars; concentrates keep 6–12 months frozen and 1–2 weeks refrigerated. Vacuum-seal or tightly wrap to prevent freezer burn and hold intense aroma.
[Illustration: Small uniform cubes of frozen glace on a tray being placed into labeled freezer bags]
- Use a wide, shallow pot to maximize surface area and speed reduction by about 20–30%.
- Start with unsalted or low-sodium stock so you can control final saltiness; concentrated salts amplify.
- If you want a vegetable glace, reduce 6–8 cups of vegetable stock to about 1 cup; add a teaspoon of tomato paste for umami.
- Boost gloss and body by adding 1–2 teaspoons of gelatin per quart of stock before cooling if your bones lacked collagen.
- Label containers with contents and date; plan to use within 6 months for best flavor.
- Reserve a small amount of reduced stock at room temperature to deglaze pans for immediate sauces, then finish with fresh butter or cream.
- When reducing, maintain a gentle simmer rather than a rolling boil to avoid bitterness and cloudy finish.
- Concentrates are very salty and intensely flavored — taste sparingly and add slowly to sauces to avoid over-salting.
- Avoid reducing highly fatty or spoiled stock; rancid fat will concentrate and ruin the product. Discard any stock that smells off.
- Do not leave hot stock uncovered at room temperature for more than 2 hours before cooling to prevent bacterial growth; always cool rapidly.
- Use caution when working with hot, viscous liquids — splashes can cause severe burns.
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