Guar gum is one of several gums used in modernist cooking. It is made from the guar bean plant, typically from India. It has properties similar to xanthan gum, including thickening and emulsifying ingredients as well as retaining water and preventing syneresis. It is also often used in ice creams to prevent crystal formation.
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The normal ratio as a thickening agent is 0.1-1.25% guar gum, even if used in conjunction with other ingredients. If too much guar gum is added the dish will take on a flavor of dried beans.
It is soluble in hot or cold water, but has a longer hydration time in cold water. Guar gum also works better when mixed with neutral to slightly acidic liquids. It is often used with other ingredients such as agar and xanthan gum.