Why do hot liquids break down the structural integrity of a biscuit/cookie so much quicker than cold liquids?

Question

Edit: Thanks so much for the silver kind stranger!

Edit 2: And the others! You’ve made my day! Glad I dropped my biscuit in my tea and decided I needed answers

In: Chemistry

Answer 1

A cookie is a composite of 3 things: Carbohydrates (sugar and starch), Fat, and Protein. The carbohydrates are water soluble to varying degrees, and will dissolve faster in hotter water, because the faster-moving molecules are better able to rip the molecules of the carbohydrates apart. Fats are not water soluble, but warm liquids will soften them, making the cookie softer. Protein (from the egg and to a lesser extent, the gluten in from the flour) isn’t super water soluble, but it doesn’t contribute as much to the overall structure of the cookie as the fat and carbs do. So, hot liquids can compromise 2/3 elements of the cookie’s structure a lot faster than cold ones.