First of all, double-skin milk is steamed with eggs, and milk is sweetened. If it is not steamed, it will definitely not solidify. As for the ratio, please go to Haodou.com to find the menu. . .

Secondly, gypsum as a coagulant is used to make tofu. . .

I think I know what you mean. You think milk and soybean milk are similar in composition, so you think that since gypsum can coagulate soybean milk, it can coagulate milk. . . I haven't done this experiment, so I really can't answer "Can plaster coagulate milk?" You can try. . .

But I can tell you for sure that even if gypsum can coagulate milk, it is definitely not "double-skin milk" and it certainly won't taste very good-you can probably imagine the taste of gypsum tofu ~