How to turn past-their-best summer berries into a refreshing drink – recipe

In the height of summer, strawberries ripen quickly, and often go soft and unpalatable. At this stage, before they turn mouldy, they are perfect for fermenting, not least because these are signs that the process has already begun. Lacto-fermented berries keep in the fridge for at least a month and are delicious on pancakes, waffles, granola or as a condiment for savoury dishes. To make them, pack ripe berries into a clean jar and stir in a tablespoon of raw honey for every 100g fruit. Top with a little water to cover, seal and leave at room temperature and out of direct sunlight for one to two days, stirring three times a day, until the fruit starts to bubble and turns effervescent. Blend or leave whole, then seal and store in the fridge.

Kvass is another great way to preserve fruit. This ancient Baltic beverage is traditionally made with bread and sometimes flavoured with berries, apples and raisins. My simplified, gluten-free version makes a delightful fizzy drink that’s similar to kombucha or water kefir.

Fermented berry kvass
Unlike kombucha and water kefir, no special ingredients are required to make this kvass; all you need is a little time and patience. Strawberries make a wonderfully pink kvass, but any soft fruit, or combination of fruits, will also work. Because of the high yeast content in fruit, mould can form on the surface while you’re making this, so, prevent this from happening, and to aid fermentation, agitate and renew the surface by stirring it vigorously a few times every day.

Chlorine can inhibit fermentation, so, if possible, dechlorinate the water by pouring it into a wide-mouthed jar up to 24 hours ahead of making your kvass. After fermentation, the mushy fruit solids strained from the liquid can be saved and enjoyed as a puree on porridge, pancakes or waffles.

Enjoy this spritzy and nutritious drink as it is or over ice with a wedge of lime and sprig of mint for extra aroma.

Makes 1 cup

Strawberries or other berries
½ tbsp honey or maple syrup, per 100g fruit
1 pinch sea salt, per 100g fruit
250ml water, per 100g fruit

To serve (optional)
Ice, a lime wedge and/or a mint sprig

Multiply the quantity of honey, salt and water depending on how many berries you have to use up.

Put everything in a suitably sized clean jar or jars, then seal, shake and put out of direct sunlight, and leave to ferment, stirring the mix vigorously two or three times a day. After several days, when the berries look cooked and the mixture has turned darker and effervescent, strain into bottles and seal. Leave for two more days, until the kvass becomes more bubbly (fermentation times will vary depending on your room temperature). Prevent the bottles becoming too carbonated (and so at risk of exploding), by opening them every day and letting any excess gas escape. Once ready, consume or store in the fridge.