We clean the cabbage well, removing the outer leaves that are ugly. We cut into quarters, remove the central log and weigh it. In our case it was 1,200 kg. This information is essential for calculate well the amount of coarse salt, which must be 2% of the weight of the cabbage. In this case, 24 grams.
With a very sharp knife or a mandolin we cut the cabbage into thin strips. We introduce it in a wide and deep container, add the coarse salt and, with well-cleaned hands, massage so that the salt I got to all the strips cabbage. Let it rest for six hours, during which time the salt will make the cabbage release its juices.
After the resting time has elapsed, if the cabbage has not been completely covered with liquid (it will depend on the type of cabbage we use), add boiled and cooled water up to cover. We put some weight on the cabbage so that it is completely submerged in liquid (we have used a plate and a mortar), cover with a kitchen cloth and let it ferment for a minimum of a couple of weeks.
The ideal fermentation temperature ranges between 18ºC and 20ºC, It is convenient that the place where we leave it to ferment is cool and dry. In a matter of a few hours you begin to see CO2 bubbles rising to the surface, this is perfectly normal. As the days go by the cabbage becomes more tender and the taste more acidic.
After two weeks the cabbage is appreciably fermented and can be eaten. However, you can also let ferment longer if you want to obtain more complex flavors. Once ready, we transfer the sauerkraut to jars and store it in the fridge. Holds months at low temperature.