Bottling, Canning and Fermentation

Water-bath canning is simple, safe and transformative for high-acid crops: tomatoes, pickles, chutneys, jams, fruit in syrup. You need clean jars, new lids, a large pan deep enough to cover jars by 3cm, and a thermometer. The principle is heating filled jars to 85–100°C for a specific time, which kills spoilage organisms and creates a vacuum seal as the contents cool.

Tomatoes can be canned as passata, whole peeled, or chopped. Add 1 tablespoon lemon juice or ½ teaspoon citric acid per 500ml jar to guarantee acidity above pH 4.5 — modern tomato varieties are often less acidic than older types, and botulism thrives in low-acid environments. Process pint jars for 40 minutes at a rolling boil. The ping of a sealed lid is unmistakable.

Fermentation requires no heat, no special equipment, just salt, time and airlocks if you want to be tidy. Sauerkraut is shredded cabbage massaged with 2% salt by weight, packed into jars, submerged under brine and left at 18–22°C for two to six weeks. Lactobacillus bacteria acidify the environment naturally, preventing spoilage. Kimchi, pickled cucumbers, fermented green tomatoes and hot sauce all follow the same logic. Taste weekly; refrigerate when you like the flavour.