Why does milk curdle in tea?

Curdling of milk in tea is a phenomenon that occurs due to chemical reactions between certain ingredients in milk and tea. Here are the main reasons why milk can curdle in tea:

1. Acidity of Tea : Tea contains tannins, which not only give flavor and color to tea but also have a slightly acidic nature. If the acid concentration in tea is high enough, it can cause the casein, a protein in milk, to denature. This leads to a separation of the milk components, which is perceived as curdling.

2. Temperature of the tea : Hot tea can also help curdle the milk. Extreme heat can cause the proteins in milk (mainly casein) to change structure and visibly settle.

3. Freshness of Milk : The freshness of milk plays a role in the coagulation process. Older milk that is nearing its shelf life often has slightly increased acidity, increasing the risk of curdling in hot tea.

4. Order of Addition : The way milk is added to tea can also have an impact. When milk is poured into a cup of hot water, the sudden difference in temperature can cause the milk protein to precipitate. Adding tea to milk can reduce this risk because the temperature rise is more gradual.

5. Type of tea : Certain types of tea, especially those higher in tannins (like some types of black tea), may be more likely to cause milk to curdle than others.

To prevent milk from curdling in tea, the following steps can be helpful:

• Use fresh milk.
• Add the milk to the cup before making tea.
• Avoid using extremely hot tea.
• Choose teas with a lower tannin content.