Add the red cabbage to a large mixing bowl and scatter over the salt. Use your hands to massage the salt firmly into the cabbage, bruising the flesh and pressing it all together. Cover loosely with a clean tea towel and leave for 2 hours to allow the salt to draw out the moisture. After 2 hours, tip into a colander, rinse well under cold running water and drain well.
Rinse out the mixing bowl, and add the ginger, garlic, water or kefir water, gochugaru, fish sauce, sesame seeds, sugar, sea salt and a grind of black pepper. Stir well until you have a pungent paste, add the rinsed cabbage back in and mix together thoroughly. Spoon into the jar, or jars, packing down well so it all fits snugly – the top should be submerged in liquid. Tear off a piece of clingfilm and press it tightly down onto the surface to keep out as much air as possible then cover tightly with the lid. Leave to ferment at room temperature for 3-7 days.
Check the kimchi every day, pressing the cabbage back under the surface liquid and replacing the clingfilm layer with fresh. Start tasting after 3 days – it should be pleasantly sour – leave it for longer if necessary. Much depends on the temperature and your personal taste. Once you’re happy, store it in the fridge, where it will keep maturing nicely for a few months.
