How can you prevent milk from curdling during cooking?

There are three main causes of milk curdling during cooking, namely acid, such as lemon or lime juice, for instance; excessive heat and salt. The only way milk can defend itself against these factors is through its fat content, so using full fat milk will immediately reduce the risk, while skimmed or semi skimmed milk will invite curdling.

The same principle applies to cooking with cream. It may not be a good thing for those counting calories or worried about cholesterol, but to prevent curdling heavy cream is definitely better than light cream in cooking.

• Adding the Milk Last

Another way to avoid curdling is to add the milk at the last minute, just before the dish is to be served, if possible. If a lot of milk is required, it may need re-heating. This process should be kept as short as possible, and the temperature should not be allowed to rise above 180 degrees F, or 82 degrees C. Salt should also not be added until just before serving.

• Pre-Warming Milk

Taking a little of the already hot stock and stirring it into the milk to pre-warm it a little before pouring it into the pot will also help. Milk should always be allowed to get to at least room temperature before adding it to boiling pots. Ice cold milk added to hot ingredients basically equals instant curdling.

• Reducing Heat

If it seems likely that the milk is going to curdle, the best thing to do is to either drastically reduce the heat or, better still, remove the pot from the heat altogether and then add the milk, stirring continuously.

• Baking Soda

Apparently adding just a tiny pinch of baking soda to the milk when boiling it will also keep it fresh and prevent it from curdling.