The Still Room
Preserving what you grew: drying, bottling and the safety line
A glut is a problem, not a triumph. Drying, bottling and fermenting are the three answers — and one of them has a hard safety line running through it that is worth understanding properly.
The short answer
High-acid foods — most fruit, pickles, jams, tomatoes with added acid — can be safely preserved by water-bath bottling at home. Low-acid foods, including vegetables, meat and untreated tomatoes, cannot: they require pressure canning to reach 116 °C, because Clostridium botulinum spores survive boiling. This is the one rule in preserving that has no exceptions.
Every productive garden eventually produces more than a household can eat, all in the same fortnight. That is the point at which preserving stops being a hobby and becomes the thing that decides whether the growing was worth it.
There are three methods worth knowing, and one safety rule that genuinely matters.
The rule, first
Clostridium botulinum spores survive boiling. They are widespread in soil, they are harmless in the presence of acid or oxygen, and in a sealed, low-acid, oxygen-free jar at room temperature they produce one of the most dangerous toxins known.
The dividing line is pH 4.6. Above that acidity — most fruit, jams, pickles in vinegar, chutneys — a water bath at 100 °C is sufficient, because the acid prevents the spores from germinating. Below it — beans, carrots, meat, plain tomatoes, most vegetables — a water bath is not sufficient, and no amount of extra boiling time changes that. Those foods require a pressure canner reaching 116 °C.
This is not a matter of technique or confidence. It is chemistry, and it is the one place in this entire site where we will simply tell you not to improvise.
| Food | pH | Safe method |
|---|---|---|
| Jams, jellies, fruit in syrup | High acid | Water bath |
| Pickles and achar in vinegar | High acid | Water bath |
| Chutneys | High acid | Water bath |
| Tomatoes with added lemon juice or citric acid | High acid | Water bath |
| Tomatoes, plain | Borderline | Pressure canner, or add acid |
| Beans, carrots, most vegetables | Low acid | Pressure canner only |
| Meat, poultry, stock | Low acid | Pressure canner only |
| No exceptions | The line is pH 4.6 |
Drying, which is ours
South Africa has a preserving tradition that most of the world does not, and it is built on drying rather than bottling: biltong, droëwors, dried fruit, mebos.
That is not an accident. Our climate — low humidity, warm, with reliable moving air — is close to ideal for drying, and it needs no equipment, no seals and no pressure vessel. It also carries a fraction of the risk of bottling, because you are removing water rather than creating a sealed anaerobic environment.
If you are starting somewhere, start here. It is the method our conditions are built for.
Fermenting, which does the work for you
Sauerkraut, kimchi, achar, sourdough. Fermentation preserves by producing acid rather than by applying heat, which means it needs no equipment at all — a jar, salt and patience.
It also sits on the safe side of the acidity line by design, because the acid is what the process makes. A properly fermented vegetable is self-protecting.
Labelling, which sounds trivial and is not
Date every jar with the day it was made, not a guessed expiry. Note the method and, for anything bottled, note whether acid was added.
A year later you will not remember, and with preserved food the thing you cannot remember is exactly the thing that matters.