Freeze-drying sounds complicated, but the idea is simple: first we freeze, then we remove the water under vacuum. Below we describe what happens to the sweets at each stage.
Step 1: freezing ❄️
We lay the sweets out on trays and put them in the freeze dryer. The machine chills them far below zero until all the water inside turns to ice. Fast, deep freezing matters, because it decides how evenly the sweets dry.
Step 2: vacuum and sublimation 🌬️
Once everything is frozen, a pump sucks the air out of the chamber. At very low pressure the ice doesn't melt; it turns straight into vapour. This process is called sublimation. The vapour goes to a cold condenser, where it freezes again, so it doesn't get back into the sweets.
At the same time, the air trapped inside candies and gummies expands. That's why sweets puff up, crack and get bigger than they were before freeze-drying.
Step 3: final drying 🔥
Finally, the freeze dryer gently warms the trays to remove the last traces of moisture. The temperature is low, so the sweets don't melt. After this stage they have a porous, dry structure that crunches.
Step 4: packing 📦
Freeze-dried sweets soak up moisture from the air very easily. That's why we pack them into airtight bags as soon as they come out of the freeze dryer. It's worth treating them the same way at home, as we explain in our guide on how to store freeze-dried sweets.
How long does it take? ⏱️
The whole process takes many hours. It depends on the type of sweets, their size and how many are in the chamber. That's why we freeze-dry in batches, and it can't be rushed without losing quality.
What next? 👉
Now you know how freeze-drying works. Find out which sweets work best, or go back to our guide to freeze-dried sweets.