It is possible to cold brew tea in milk, but it may change the taste and texture of the final product. Cold brewing tea in milk may result in a creamier and sweeter taste due to the lactose present in the milk. However, the milk may also cause the tea to become cloudy and may affect the colour of the tea.
It's also important to note that using milk that is not pasteurized can be a potential health hazard, therefore it's better to avoid brewing tea in non-pasteurized milk.
It is recommended to use a non-dairy milk alternative like almond, soy, or oat milk instead of cow's milk for cold brewing tea.