Milk and flour don't grow for two reasons. One is that the yeast has expired, and the other is that the bacteria in it have been destroyed by boiling water.

Please use unexpired yeast and use warm water and flour.

Advantages of milk and flour:

Milk protein can strengthen the dough's strength, so the noodles are not easy to break, the steamed bread is elastic, the jiaozi is not broken, and the bread is more fluffy.

In fermented flour food, a large number of B vitamins and amino acids in milk can also provide sufficient nutrition for yeast, so the fermentation effect is better, the dough expands and the aroma is rich.