Freeze-dried sweets look like magic, but there's simple physics behind everything they do. Here are seven fun facts.
1. Ice turns into vapour without melting ❄️
At very low pressure in a freeze dryer, ice turns straight into vapour. This is called sublimation, and it's what freeze-drying is all about. More in how freeze-drying sweets works.
2. Sweets puff up because of the air inside 💥
Chewy candy and gummies contain tiny air bubbles. Under vacuum they expand and the sweet grows.
3. Chocolate barely changes 🍫
It has little water and a lot of fat, so there's nothing for the freeze dryer to remove. Details in which sweets can be freeze-dried.
4. Ice cream stops melting 🍦
Without water there's nothing to melt, so freeze-dried ice cream can be kept in the cupboard.
5. They're lighter, but not healthier ⚖️
Freeze-drying removes water, not sugar. Per 100 g there's even more sugar than in the regular version.
6. Moisture is their biggest enemy 💧
Freeze-dried sweets soak up moisture from the air and go soft. That's why they need to be kept in an airtight bag. See how to store them.
7. The same method makes instant coffee ☕
Freeze-drying is also used for coffee, fruit and food in space. More in our post on freeze-drying food.