Preserve the harvest

Drying works when food loses water faster than organisms can grow in it: warm air, dry air, moving air — and movement matters most.

• Slice thin and even: 3–6 mm for fruit and vegetables, about 5 mm for meat strips. Thick pieces case-harden — the outside seals while the inside stays wet and rots.
• Trim the fat off meat. Fat does not dry; it goes rancid.
• Heat meat to 71 °C (poultry 74 °C) before or after drying. Drying alone does not kill Salmonella or E. coli.
• Blanch most vegetables 2–4 minutes first, to stop the enzymes that destroy colour and vitamins in store.
• Needs air above about 30 °C and below about 60% humidity; in humid climates dry over a fire instead.

Done when jerky bends and cracks without snapping, fruit is leathery with no moisture when torn and pressed, vegetables are brittle.

Salt preserves by pulling water out and binding what remains.

• Dry salting: pack in layers with salt between each, roughly 1 part salt to 3 parts fish by weight for a hard cure. The salt draws out liquid that becomes brine — drain it for a dry cure, keep the food submerged for a wet one.
• Brining: a saturated brine is 26% salt — about 360 g per litre of water, and it will dissolve no more.
• Salt cod — split, salted, air-dried — keeps for years and is soaked in several changes of water over 24–48 hours before use.

If you have no salt, getting it becomes a priority in its own right: seawater evaporation, a salt spring, a salt lick, or trade. See salt.

Confusing these two is how people poison themselves with food they believe is preserved.

• Cold smoking keeps the smoke below about 30 °C. It flavours and dries the surface. It does not cook and it does not preserve on its own — the food must be properly salted first, and it is still raw afterwards.
• Hot smoking cooks as it smokes: fish should reach an internal 63 °C for 30 minutes. It keeps days to weeks, not months, unless it is also dried hard.

For anything meant to keep past a month, combine salting, smoking and drying — that redundancy is why traditional methods are safe.

Salt the vegetables enough that spoilage organisms struggle, exclude air, and the lactic bacteria already on the leaves win — dropping the pH below 4, where almost nothing survives.

1. Shred, weigh, and add 2–2.5% of that weight in salt — 20–25 g per kg. Plain salt, not iodised.
2. Pound until it releases its own liquid, pack hard, and make sure the brine covers everything; top up with a 2% brine if not.
3. Weight it down. Anything above the brine moulds.
4. Ferment at 18–22 °C for 3–6 weeks. Warmer goes soft; above about 24 °C it spoils.

A flat, white, wrinkled film is kahm yeast — harmless, skim it. Fuzzy or coloured growth is mould: remove well below it, and discard the batch if what is underneath is slimy or smells rotten rather than sour.

A root cellar is a controlled climate: cool, humid, dark, ventilated. It is a building project — start it in spring, not in October.

Crops do not want the same conditions and several damage each other:

• Potatoes 4–10 °C, 90–95% humidity, in the dark — light turns them green and green potato is toxic.
• Carrots, beets, turnips 0–2 °C, 90–95%, packed in damp sand.
• Cabbage 0–1 °C — and stored apart, because the smell taints everything.
• Onions and garlic 0–4 °C but dry, 60–70% — damp rots them.
• Squash and pumpkins 10–13 °C, drier, and never cold.
• Apples release ethylene, which sprouts potatoes and makes carrots bitter. Separate space.

Below about 13% moisture grain keeps; above it, it heats, moulds and sprouts.

The salt test, without instruments: a handful of completely dry salt in a dry sealed jar with a few handfuls of grain, shaken for a minute and left 15 minutes. If salt sticks to the glass or clumps, the grain is above about 15% — dry it further, spread thin and turned.

Aflatoxin is the hazard that matters: Aspergillus on damp-stored maize and groundnuts produces a potent liver toxin that survives cooking — an outbreak in Kenya in 2004 killed 125 people from home-stored maize. Sort out discoloured and mouldy kernels, and never feed mouldy grain to animals either, because it comes back in the milk.

Store raised, sealed and rat-guarded — see the granary.

Clostridium botulinum makes the most toxic substance commonly met in food. Its spores survive boiling; it grows only where there is no oxygen, low acidity and moisture — the inside of a sealed jar or a sausage. You cannot see, smell or taste it.

• pH 4.6 is the line. Below it — most fruit, and vegetables pickled in vinegar of at least 5% acidity — a boiling-water bath is enough.
• Above it — vegetables, meat, fish, beans — needs 116–121 °C, which means a pressure canner at 10–15 psi. Boiling water reaches 100 °C and creates exactly the conditions botulism needs.
• Never store garlic or herbs under oil at room temperature.
• No honey for infants under 12 months.
• If a home-canned low-acid food is in doubt, boil it hard for 10 minutes before tasting — the toxin, unlike the spores, is destroyed above 85 °C.

Preserve in more than one place. One fire, one flood or one rodent breach must not take the year.

Then rotate: label everything with what it is and when it was made, and eat the oldest first. A store that is never rotated quietly fills with food that has passed its keeping time, and the group discovers this in the month it can least afford to.

Check the whole store monthly: a single rotting item spreads, and damp found in November is fixable in a way that damp found in March is not.