Sauerkraut has long been a great way of extending the longevity of cabbage, but what does that mean for that jar of sauerkraut that you opened the other day for some delicious Reuben-style brats?

Please note, if mould forms on your sauerkraut at any point, discard the batch and start again. For this recipe you will need a 750ml/1⅓ pint clip top jar (such as a Kilner jar), a large mixing ...