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Step-by-Step Tutorial
PRACTICAL WALKTHROUGH · PARAMETERS · COMMON MISTAKES
Dehydration removes free water by heat or solar exposure, while freeze‑drying sublimates ice under vacuum to preserve structure and nutrients.
Origin: Middle Eastern, Asian, Japanese (Ancient to modern) — Middle East, Asia, Japan
See full technique reference →In hot‑air dehydration, water evaporates as vapor driven by temperature and reduced humidity, lowering water activity (a_w) below 0.6 to inhibit bacterial growth. Freeze‑drying first freezes the product at –40 °C to form small ice crystals, then primary drying sublimates ~90 % of water at –30 to –20 °C under <0.1 mbar, and secondary drying removes bound water at 20–30 °C, achieving a_w < 0.1.
Primary Reaction
Evaporation (hot‑air) or sublimation (freeze‑drying)
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