TempoLife › Features › Home preserving: freezing, pickling, fermenting and jam › cabbage

Cabbage

Cabbage is the crop this whole tradition was built around: cheap by the sack in October, dense with vitamin C, and it turns into something better than it started as. A head of white cabbage will keep on a cellar shelf for months, but shredded and salted it will keep past spring and gain flavour on the way.

The season

Storage cabbage is cut from September to late October, after the first light frosts have sweetened it. Early summer cabbage from July is for eating, not for keeping.

Acidity decides the method

Raw cabbage is low-acid, around pH 5.2–6.0. Fermented into sauerkraut it drops to roughly 3.4–3.6.

This is a reference guide, not a recipe authority and not medical advice. The one organism the safety rules here are written against is Clostridium botulinum, and the one way to be protected against it is a tested recipe followed exactly — substitutions of the acid, the sugar or the salt are not cosmetic. Where the national food authority publishes advice for a specific food (Baltic fish, wild mushrooms), that advice outranks this page.

Method by method

The classic preparation: Sauerkraut — hapukapsas, hapankaali, kvashenaya kapusta

Weigh the shredded cabbage. Add 20–25 g of plain, non-iodised salt per kilo — 2 to 2.5 % — and work it hard with your hands for several minutes until it slumps and releases enough of its own liquid to cover itself. Pack into a crock or jar and press down until the brine rises above the cabbage. Weight everything under the surface. Leave at 18–22 °C with a way for the carbon dioxide to escape; the classic additions are caraway seed, grated carrot, a bay leaf, and in the eastern Baltic a handful of lingonberries or cranberries. It bubbles for the first week, quietens in the second, and is fully sour at three to four weeks at 21–24 °C or five to six at 16–18 °C. Then it goes cold, where it will hold until the next crop.

Preparation that matters

Discard the outer leaves, quarter the head and cut out the hard core — it does not soften and it does not ferment. Shred as finely as you have patience for: fine shreds release their liquid faster and pack tighter, which matters because packing tight is what keeps air out. Salt goes on by weight, not by eye. If after twenty minutes of working and pressing there is still not enough liquid to cover, make up the difference with a 2 % brine rather than plain water, so you do not dilute what is there.

What the preserve is worth

Fermenting is the kindest method available to cabbage. Nothing is heated, so most of the vitamin C survives, and the lactic bacteria add some B vitamins as they work — this is the reason sauerkraut earned its reputation as a shipboard anti-scurvy ration. What it adds is sodium, at roughly two grams of salt per hundred grams of cabbage, so a portion is a salty food. The brine holds a share of the water-soluble vitamins; the Baltic habit of drinking it is not a bad one.

The ways this goes wrong

• Cabbage floating above the brine, which is where every failed batch starts.
• Salting by spoon rather than by scale. Coarse and fine salt differ by nearly half at the same volume.
• A warm kitchen above 24 °C, which gives soft, yeasty kraut.
• Adding vinegar, which kills the fermentation you are trying to start.

Safety rules, temperatures, blanching times, headspace and the pH 4.6 line: USDA Complete Guide to Home Canning and the National Center for Home Food Preservation guidance (US Government / land-grant publications, public domain). Acidity classes: the FDA's published approximate-pH tables. Jam composition: Directive 2001/113/EC. Fish freezing before raw or lightly cured use: Regulation (EC) No 853/2004, Annex III. Checked 2026-09-06.

Sources for this food

• USDA Complete Guide to Home Canning, fermented products (public domain)

Frequently asked questions

Related pages