Amount of liquid:
- A small amount of starch in proportion to the liquid = a runny sauce.
- A large amount of starch – thicker sauce.
Types of starch used: Cornflour is better than flour for thickening because it is pure starch.
Temperature: Requires hot, moist conditions. Starch will not dissolve in cold water and cannot thicken cool liquids. It will start to thicken between 75-87ºC.
Stirring: Essential for the creation of a smooth, gelatinised sauce. If not used, starch grains will absorb liquid and stop liquid reaching other grains = lumpy.
Sugar: Competes with starch for water. Sugar makes sauce runnier and less likely to remain stable.
Acids: Added after it has thickened or it can break down.