Preserving food

Making a glut last, without making anyone ill.

• Water bath or pressure: choosing correctlyThe single most dangerous decision in home preserving. One number decides it, pH 4.6, and getting it wrong is how botulism happens. Read this before any other page in this domain.
• Water bath canning, jar to sealThe safe method for acid foods, and the backbone of the British preserving tradition. Jar preparation, headspace, processing and the seal check that decides whether it goes in the cupboard or the fridge.
• Pressure canning, operationallyThe only method that makes low-acid food shelf stable. It is temperature that does the work, not pressure, and that distinction explains the ten-minute venting step almost everyone skips.
• Recognising canning failureHow to judge a suspect jar without tasting it, and the honest limit of what looking and smelling can tell you. Botulinum toxin is odourless and tasteless, so your senses are not the test.
• Dry food, and make jerky safelyDrying fruit and vegetables is forgiving. Drying meat is not, and the reason is counterintuitive: drying makes bacteria harder to kill, not easier, so meat must be heated before it goes in.
• Ferment vegetablesSalt, vegetables, water and time. No fuel, no jars to process, no equipment. Two numbers matter: 2 to 3% salt by weight, and everything stays under the brine.
• Yoghurt and soft cheeseTurning milk that will not keep into food that will, with two temperatures: scald at 82 to 85°C, then hold at 43°C. Both are the whole technique.
• Cure meat and fishSalt, and for anything smoked or long-kept, a measured quantity of curing salt. This is the one page in the app where a 0.1 g kitchen scale is a safety instrument rather than a convenience.
• Hot and cold smokingHot smoking cooks and is forgiving. Cold smoking does not cook, spends its entire duration inside the danger zone, and is only safe on meat that was properly cured first. Know which one you are doing.
• Render tallow and lardTurning raw fat into a shelf-stable cooking fat, a candle material and a soap ingredient. Wet rendering with salt gives a cleaner, longer-keeping result, and the difference is worth the extra hour.
• Root cellaringStoring a harvest with no fuel, no jars and no processing at all. Two things decide whether it works: matching each crop to the right temperature and humidity, and keeping the ethylene producers well away from everything else.
• Make pemmicanEqual weights of bone-dry powdered meat and pure rendered fat. Keeps for years at room temperature with no processing, no jars and no power, because there is no water in it for anything to grow in.
• Water-glass eggsFresh unwashed eggs kept a year or more in a lime solution, no refrigeration and no fuel. It only works on eggs that still have their bloom, which rules out every egg in a supermarket.
• Make vinegar from a motherFree vinegar from windfalls, scraps and leftover wine, indefinitely. With one hard limitation that cuts against the whole self-sufficiency instinct: you must not use it for pickling or canning.
• Sprouting seeds, and its real riskFresh green food in three days, in a jar, in winter, with no soil or light. It is also a genuinely high-risk food, home growing does not make it safer, and the honest recommendation is to cook them.