Bottling and Jam Making

Bottling fruit and making jam are the classic Kiwi preserving traditions, the ones that fill a pantry shelf with summer for the year ahead. Both rely on the same principle: high acid and sugar, plus heat, make food keep safely at room temperature.

The high-acid rule

Home water-bath bottling is only safe for high-acid foods: most fruit, jams, pickles and tomatoes with added lemon juice or citric acid. Low-acid foods such as plain vegetables, beans and meat are not safe to bottle this way, because they can harbour botulism, and they need a pressure canner instead. Stick to fruit and jam and you are working within the safe zone that generations of preservers have relied on.

Bottling fruit

Stone fruit, apples, pears and berries bottle well. Pack prepared fruit into clean jars, cover with syrup or juice, and process in a water bath or preserving unit so the contents heat through and the lids seal as they cool. A properly sealed jar pulls its lid down tight and keeps for a year or more in a cool, dark cupboard. Any jar that does not seal goes in the fridge to use soon.

• Use clean, undamaged jars and fresh lids or seals
• Process so the contents are heated right through, then let lids seal on cooling
• Check the seal before storing, and refrigerate any that did not take
• Label with the contents and date, and store cool and dark

Getting jam to set

Jam sets when acid, sugar and pectin come together at the right temperature. High-pectin fruits like apples, plums and citrus set easily, while low-pectin fruits like strawberries need added lemon juice or a setting sugar. Boil to setting point and test on a cold saucer: the jam should wrinkle when pushed. Bottle hot into clean jars and seal. If a batch will not set, it usually needs more acid or a longer boil rather than more sugar.