thumb|A [[cheesemaker checks the set of milk curd after vegetable rennet was added to milk]]
Curdling is the breaking of an emulsion or colloid into large parts of different composition through the physio-chemical processes of flocculation, creaming, and coalescence. Curdling is purposeful in the production of cheese curd and tofu, but undesirable in the production of a sauce, cheese fondue or a custard.
Egg sauces
In hot preparations emulsified with eggs like hollandaise and custard, curdling is the undesirable result of overheating the sauce. Sauces which contain starch curdle with more difficulty.
In cold sauces like mayonnaise as well as in hot sauces, too large a ratio of fat to egg may also cause curdling.
Milk sauces
In sauces which include milk or yogurt, overheating often causes curdling. The higher the fat content, the less likely curdling is. Strained yogurt used in sauces also curdles only with difficulty.
Coffee
When a plant based milk such as soya milk is added to coffee, curdling can sometimes occur. To help prevent this manufacturers sometimes add acidity regulators.
Cheesecake
When making cheesecake, if water is added to the cream cheese during the combining period, it will curdle.
See also
- Cottage cheese
- Junket
Bibliography
- Harold McGee, On Food and Cooking: The Science And Lore Of The Kitchen, 1984–2004.
- Bethany Moncel "Why Does Milk Curdle" . Foodreference.about.com.