Recipe: Lacto-fermented Blueberry Jam

If you’re familiar with making homemade jam, then you’re probably used to a process that involves adding lots of sugar and pectin to cooked fruit to create a thick jam consistency. This recipe is very different. Many fruits naturally contain pectin, which comes out in the cooking process. Instead of water bath-canning the jam, this recipe uses lacto-fermentation to preserve the fruit. The high sugar content of fruits and jams can make lacto-fermentation tricky as the sugars tend to convert to alcohol quickly. That is why the use of a starter culture is important. Salt is also added to this jam, giving it a unique flavor and helping with preservation.


  • Generous 2 lbs. of blueberries
  • 3/4 cup honey or Sucanat
  • 2 tsp. sea salt
  • 1/3 cup whey from yogurt or kefir


  1. Combine blueberries, sweetener, and salt in a small saucepan. Cook for five minutes at a simmer, smashing the blueberries as they cook to allow juices to release.
  2. Remove from heat and allow to cool to room temperature.
  3. Once blueberry mixture has cooled, mix in the whey (water kefir can be used as a direct substitution for whey). Transfer to very clean jam jars and seal tightly. Allow to ferment at room temperature for about 2 days. Burp jars if you notice excess gases building up.
  4. Move the jar to cold storage where it should keep for a couple of months.