Leaving to ferment
Screw on the lid but do not seal completely (if using a clip top jar, don’t fully fasten the clip), as gas still needs to escape during the fermentation process. Place the jar on a plate or bowl to catch any overflow juices during fermentation. Store in a dark place (18°C-22°C) for at least 7 days. After 2-3 days, the mixture should start to bubble. If the temperature is below 18°C, this may take longer.
After 7 days (at 18°C-22°C) you can open the jar to taste. If the brine level has dropped, add more 2% salt-water solution to top it up to a 1cm depth. At this point the sauerkraut is ready to eat, but leaving it (with the lid loose to allow gas to escape) for up to 4 weeks will enhance the flavour. When ready, seal the jar fully and transfer to the fridge, where it will keep for up to 6 months*.
The time you leave the sauerkraut depends on how salty, sour and crunchy you like it. Taste after 7 days to check flavour and texture. Remember, the more you open the jar, the more likely it is to spoil.
*If the sauerkraut starts to smell, becomes discoloured or slimy, it is contaminated and will need to be discarded.