Every cell is mostly water. As a piece of food is cooled below freezing, that water nucleates into ice crystals — and the rate of cooling decides where those crystals grow and how big they get. Slow freezing (a home freezer, roughly -1 to -5 °C/min) gives water time to migrate out of cells before it freezes, so a few large, jagged crystals grow in the spaces between cells and mechanically puncture the surrounding cell walls as they expand. Cryogenic freezing with liquid nitrogen (around -196 °C, tens to hundreds of °C/min) removes heat so fast that water freezes almost where it stands — thousands of tiny crystals form both inside and between cells, too small to tear the membranes apart.
Q = m·c·ΔT (heat that must leave the food)
cooling rate = ΔT/Δt (°C per minute)
crystal size ∝ 1 / cooling rate
- Freeze duration — how long the animation takes to reach 100% for both blocks; the underlying cooling-rate difference between the two methods stays the same either way.
- Ice crystals — toggle the crystal shards to isolate the effect of crystal size alone from the cell-colour damage indicator.
- Replay — reset both blocks to freshly-cut, undamaged tissue and run the comparison again.
- Each cell has its own random rupture threshold (real tissue is not uniformly strong), so damage spreads unevenly across the block exactly as it does in a real sample.
Real-world relevance: this is why flash-frozen (IQF / cryogenic) produce keeps a fresh texture on thawing while slow home-freezer freezing leaves fruit and meat mushy — the food isn't chemically different, its cell walls are simply intact or shredded.