Practical guides
Food-by-food drying guide
Ninety-six foods with the numbers that matter: how to prepare them, what to pretreat with, what temperature, how long, how dry, and what you get back. Search it, filter it, sort it, and click any row for the full detail.
Times assume a fan-assisted dryer with good airflow, single-layer loading, and moderate ambient humidity. They are typical ranges for planning, not specifications. Your dryer, your slices and your climate will move them. Confirm doneness with a weight check or a water-activity reading, never with the clock.
The guide
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Understanding yields and water loss
The “yield” column is the fresh-to-dry mass ratio. It is not a fixed property of a food — it falls directly out of the moisture content before and after drying, and you can calculate it exactly:
| Food group | Typical fresh moisture | Typical yield ratio | What that means in practice |
|---|---|---|---|
| Leafy herbs | 75–85 % | 8–14 : 1 | A huge bag of basil becomes a small jar — plan storage accordingly |
| Leafy vegetables | 85–93 % | 10–18 : 1 | Great for volume reduction; low mass yield |
| Root vegetables | 80–90 % | 6–12 : 1 | Reliable, high-value soup-mix ingredients |
| Fruit | 80–90 % | 4–10 : 1 | Sugar and solids raise the yield; berries are the worst |
| Mushrooms | 88–92 % | 12–16 : 1 | Dramatic shrinkage; flavour concentration is the payoff |
| Meat (jerky) | 70–75 % | 2.5–3.5 : 1 | High-value per kilogram; watch the lethality step |
| Fish | 70–80 % | 3–5 : 1 | Oily fish shrinks less but spoils faster |
| Fruit leather / purée | 80–90 % | 5–9 : 1 | Yield depends on sugar and purée solids |
| Nuts & seeds | 3–8 % | 1.1–1.3 : 1 | Almost no water to lose — the job is restoring crispness and slowing rancidity |
| Citrus peel & slices | 70–85 % | 4–9 : 1 | Peel and pith hold far more water than the juice segments |
Food groups at a glance
🍎 Fruit
135 °F, 6–48 h, target 12–20 % moisture. Pretreat with ascorbic/citric or sulfite dips; crack skins of thick-skinned fruit.
Filter to fruit →🥕 Vegetables
125 °F, 4–20 h, target 6–8 % moisture. Blanch almost everything first; drain and blot before loading.
Filter to vegetables →🌿 Herbs
95–110 °F, 2–6 h, target ≤ 5 % moisture. Cool, fast, shaded. Store whole and crush at the last moment.
Filter to herbs →🥩 Meat & fish
Jerky 145–160 °F with a 160/165 °F lethality step; fish 130–140 °F after curing. Target MPR ≤ 0.75:1 for jerky.
Jerky safety rules →🍄 Mushrooms
115–125 °F, 4–12 h, target 6–8 % moisture. Brush clean rather than washing. Umami intensifies dramatically.
Filter to mushrooms →🥣 Leathers, purées & powders
135 °F, 4–10 h, spread 3–6 mm on a solid liner. Sweeten to taste; dry until pliable and non-sticky.
Filter to leathers →🥜 Nuts, seeds & citrus
Nuts and seeds 105–125 °F, 4–24 h, target 4–6 % moisture — they start dry, so the goal is crispness and slowing oxidation. Citrus is the opposite problem: blanch the peel to debitter, then dry it low and slow.
Filter to nuts →Nuts, seeds and citrus: what is different
Three groups sit awkwardly in a drying guide, because the logic that makes drying work for a tomato does not apply to them. Nuts and seeds arrive already low in moisture, so drying is not keeping microbes out — it is finishing the job. Citrus arrives as a watery fruit whose most interesting part, the peel, is bitterness and volatile oil rather than sugar.
Nuts and seeds: drying to finish, not to preserve
- They start dry. A shelled almond is already 4–6 % moisture. What you are removing is the water you added when you soaked them, or the water still in a fresh home harvest — then hardening the texture back up.
- Oil sets the shelf life, not water. Fats oxidise to a rancid, paint-like flavour long before any mould can grow. Oxygen is the enemy, so an oxygen absorber in a cool, dark, sealed container matters more than another hour in the dryer.
- Keep the temperature low. 105–125 °F (40–50 °C). Above that the oils begin to oxidise in the dryer, and the texture goes from crisp to greasy.
- Aflatoxin is a genuine hazard in peanuts, pistachios, Brazil nuts and figs. Any mould, discolouration, shrivelling or musty smell means discard the lot: the toxin is heat-stable and spreads well beyond the visible growth. See moulds, mycotoxins and aflatoxin.
- Salt slows drying. Seasoning before the run adds solute that holds water at the surface. Season lightly, or season again once the batch is dry.
For the crisp, slightly sweeter texture of soaked nuts: cover raw kernels with filtered water, add 1–2 % salt, soak 8–12 h (refrigerate in hot weather), drain, rinse well, then dry at 115 °F for 12–24 h until the kernels snap rather than bend. Spread them in a single layer — piled nuts dry unevenly and go musty in the middle. Be clear about what this is: a texture and flavour routine, not a safety treatment. Soaking adds water and is one more chance to introduce microbes, so work cleanly, keep it cold if it runs long, and dry the batch thoroughly.
| Group | Dry at | Target moisture | What actually limits shelf life | Store with |
|---|---|---|---|---|
| Tree nuts & peanuts | 105–125 °F | 4–6 % | Rancidity first, then mould; aflatoxin risk is in the raw material, not the drying | Oxygen absorber, cool and dark; freeze beyond 3–6 months |
| Seeds | 110–125 °F | ≤ 5 % | Rancidity — hulled sunflower and sesame turn fastest | Airtight with an oxygen absorber, in small jars used up quickly |
| Nut or seed powders | as above | ≤ 5 % | Oxidation and caking; mould if the powder picks up water | Vacuum-sealed, refrigerated after opening |
Citrus: drying the peel, not the juice
Citrus juice is mostly water and sugar, and it is a poor drying candidate. Citrus peel and zest are excellent: the oil glands in the flavedo hold the aroma you want, and drying concentrates it. The white pith underneath is what tastes bitter, so preparation is mostly about removing it or taming it.
- Zest first. Pare strips of zest with a peeler, leaving the white pith behind. For powder, dry the strips at 115–125 °F until brittle (4–8 h), then grind — not before.
- Blanch to debitter. Peel that will be eaten — candied peel, peel powder for baking — is better for 3 × 1-minute blanchings in fresh boiling water. Each blanch leaches bitter compounds out of the pith.
- Whole slices (orange, lemon, lime) dry into crisp wheels for drinks and tea: slice 3–5 mm, remove pips, 125–135 °F for 6–16 h. Turn them once early, because slices glue themselves together as they dry.
- Candied peel is a different product. Simmer peel in sugar syrup until translucent, drain, then dry only until tacky rather than wet. Sugar is a humectant, so candied peel deliberately stays soft and needs a mould inhibitor or refrigeration — see humectants and intermediate-moisture foods.
- The peel oils are volatile. Above roughly 140 °F the characteristic citrus aroma is driven off. Dry cool and low if aroma is the point.
Dried citrus is strongly hygroscopic: slices pull water out of humid air and go limp faster than most dried fruit. A desiccant in the jar, or a high-barrier pouch, earns its place here. See packaging barriers and moisture migration.