Rachel de Thample, author of The Fermentation Year, recommends fermenting whole fruit in honey as a way to extend the summer harvest. She packs fruit such as blackberries or plums into sterilised jars with enough honey to cover them, adding lemon juice or cider vinegar if the fruit has low acidity. The mixture should be left for a few weeks until it becomes slightly fizzy, then moved to the refrigerator; it will keep for up to a year at room temperature.
De Thample uses the fermented fruit with cheese, meat or fish, and the syrup can be used like maple syrup or cordial. For those looking for other options, she suggests a British-style kimchi using courgettes, blackcurrants and strawberries, or taking inspiration from Japanese umeboshi by layering plums with 15 percent salt by weight and crushing some of the fruit to create a brine. The resulting liquid can be used as a substitute for soy sauce.
Kenji Morimoto, a regular contributor to The Guardian and author of Ferment, recommends infusing damsons in flavoured liquors as another preservation method. The technique requires only vodka, the fruit and rock or granulated sugar to capture the fruit's flavour.