Cornstarch Slurry Ratio for Sauces and Gravy
Use this cornstarch slurry ratio for smooth sauces and gravy, including how much starch to use, when to add it, and how to avoid lumps.
Quick reference
- Light thickening: ½ tbsp starch per cup liquid Thin, pourable sauce
- Medium thickening: 1 tbsp starch per cup liquid Typical gravy or sauce
- Thick coating: 1½ tbsp starch per cup liquid Add gradually to avoid gelled texture
- Mixing ratio: Equal parts starch and cold water Whisk smooth before adding
The basic cornstarch slurry ratio
For most everyday sauces and gravy, start with about 1 tablespoon of cornstarch per cup of liquid. Mix the cornstarch with an equal volume of cold water until completely smooth. For a lighter, pourable sauce, start with ½ tablespoon per cup; for a thicker, spoon-coating sauce, try 1½ tablespoons. These are starting estimates: a sauce that is already reduced or thickened may need less. Add the slurry gradually so you can stop when the texture is right.
- ½ tablespoon per cup: light sauce
- 1 tablespoon per cup: medium sauce or gravy
- 1½ tablespoons per cup: thicker coating sauce
How to make and add the slurry
Whisk the cornstarch and cold water in a small bowl or cup just before using; the starch settles quickly. Bring the sauce, stock, pan juices, or gravy to a simmer first. While whisking the liquid, add the slurry gradually rather than pouring it in all at once. Stop when the sauce reaches the consistency you want—you may not need the entire mixture.
- Use cold water, not hot water, for mixing.
- Whisk continuously as you pour.
- Scrape the bowl to use all the dispersed starch.
Let the sauce thicken
After adding the slurry, keep the liquid at a gentle simmer for about 1 to 2 minutes, stirring or whisking. The sauce should become glossy and noticeably thicker. Avoid boiling excessively: prolonged, vigorous boiling can weaken the thickening and may make the texture less smooth. If the sauce is still too thin, mix another small slurry separately and add it gradually.
- Simmer briefly to activate the thickening.
- Do not add dry cornstarch directly to the pan.
- Adjust in small additions rather than over-thickening.
Fixing common problems
Lumps usually come from adding dry starch to hot liquid or from skipping the cold-water mixture. If a sauce becomes too thick, whisk in a little stock, water, milk, or other compatible liquid. If it tastes thin after simmering, make a fresh slurry and add it in small amounts. For the smoothest finish, strain the sauce if small lumps remain.
- Too thin: add more slurry gradually.
- Too thick: loosen with liquid a spoonful at a time.
- Lumpy: whisk firmly or strain before serving.
When to use less or more
The amount of cornstarch depends on the sauce's starting consistency, acid level, and ingredients. Begin with about 1 tablespoon per cup for a typical gravy, or ½ tablespoon for a light pan sauce. A thick glaze may need around 1½ tablespoons per cup, but avoid adding it all at once. Whisk part of the cold slurry into gently simmering sauce, wait a minute or two, and adjust. Adding too much at the start can produce an unpleasantly gelled texture.
- Measure the liquid before choosing the starch amount.
- Remember that the sauce thickens slightly as it cools.
- Taste and adjust seasoning after the texture is right.