Ice crystals: frozen fast is finer
Also searched as: freezing, ice crystals, creamy ice cream, crystal size
In short: When water freezes it forms crystals. Fast freezing and stirring keep them small; slow freezing makes them large and coarse.
Like snow and hail: lots of small flakes are soft, a few big grains are hard and crunch.
Simplified model
What happens
When water freezes slowly, a few crystals grow for a long time and get large. When it freezes quickly or is stirred while freezing, many seeds form at once and all stay small. Large crystals make ice cream grainy and pierce cell walls during freezing: the vegetables turn soft and leak juice when thawed. If the freezer temperature swings, small crystals grow together into large ones over time.
Why it matters
Explains why ice cream turns creamy when stirred, why you freeze things flat and fast and why thawed strawberries are mushy.
Rules of thumb
- Freeze flat, not in a thick block.
- Pre-chill the ice cream base and stir it while it freezes.
- Do not open the freezer often; temperature swings coarsen the crystals.
Levers
3
In practice
2
Desserts and sweets
An ice cream maker freezes and stirs at the same time: that is why it is finer than ice cream from the freezer.
Vegetables
Pre-freeze berries separately on a tray, and only then bag them.
Ice cream turns grainy or rock hard
Freezer burn: grey, dry patchesSources · 1
- Harold McGee: On Food and Cooking (2004)