Xanthan Gum: What It Is and How to Use It
Xanthan gum is a powdered thickener and stabilizer made by fermenting sugar with the bacterium Xanthomonas campestris. The bacteria produce a long, sugar-based polymer that's purified, dried and ground. A tiny amount, often less than 0.5% of a recipe's weight, thickens liquids, holds emulsions together and helps gluten-free doughs hold their shape.
How it works
Xanthan molecules are long, stiff chains with side branches. Dissolved in water, they tangle and form a loose network that traps water, which thickens the liquid. At rest the network is intact and the liquid is thick. When you stir, pour or chew, the chains align and slide past each other, and the liquid thins out. When you stop, it thickens again.
This behaviour is called shear-thinning. It's why a xanthan-thickened salad dressing clings to leaves but pours easily from the bottle, and why it doesn't feel gloppy in your mouth at moderate doses.
Xanthan is also unusually tough. It works:
- Cold or hot, without cooking.
- Across a wide pH range, including vinegar and lemon juice.
- Through freezing, thawing and reheating.
- In the presence of salt.
How much to use
| Use | Amount | Notes |
|---|---|---|
| Thickening a sauce, soup or gravy | 0.1–0.3% of liquid weight (about 1/4 tsp per 250 ml) | Blend in, wait a minute, add more if needed |
| Stabilizing vinaigrette | A pinch (0.1–0.2%) | Keeps oil and vinegar from separating |
| Gluten-free cookies | 1/4 tsp per cup of flour | Adds chew and holds shape |
| Gluten-free cakes, muffins | 1/2 tsp per cup of flour | Traps gas for a better rise |
| Gluten-free bread, pizza | 1 tsp per cup of flour | Mimics gluten's stretch |
| Ice cream and sorbet | 0.1–0.2% | Limits ice crystals |
Why it's used in gluten-free baking
Wheat gluten forms an elastic network that traps gas and holds bread together. Gluten-free flours can't do that. Xanthan gum adds viscosity and some elasticity to the batter, helping trap bubbles and keep baked goods from crumbling.
Common mistakes
- Using too much. Above about 1% in a liquid, texture turns slimy and stringy. In baking, excess makes gummy crumb.
- Adding it to still liquid. It clumps into "fish eyes" instantly. Blend or pre-mix it.
- Measuring loosely. Use proper measuring spoons; 1/8 tsp makes a difference.
If you don't have it, see our xanthan gum substitutes.
Questions
How much xanthan gum per cup of gluten-free flour?
A common guide is 1/4 tsp per cup (about 140 g) for cookies, 1/2 tsp for cakes and muffins, and 1 tsp for bread and pizza dough. Many gluten-free flour blends already include it, so check the label.
How do I keep xanthan gum from clumping?
Sprinkle it slowly into a blender or whisk while the liquid is moving, or mix it first with sugar, oil or the dry ingredients. Dumping it into still liquid creates gel lumps that won't dissolve.
Is xanthan gum safe to eat?
Yes, it's approved as a food additive in Canada, the US and the EU and is used in tiny amounts. Large amounts can have a laxative effect, as many fibres do.
Can xanthan gum thicken a sauce without cooking?
Yes. Unlike flour or cornstarch, xanthan gum thickens instantly, cold or hot, and doesn't need boiling. It also stays stable when frozen, reheated or mixed with acid.