Sauerkraut is one of the most identifiable fermented foods in the western world, yet it has only attained stardom in German cuisine. The method for making kraut was acquired from East Asia by the Romans — knowledge that was subsequently lost to Europe for centuries. It was reintroduced to the west by invading Tartar hordes bringing it from China, eventually making its way to Austria, where it was given its literal name “sour plant”.
This version uses kohlrabi in place of the ubiquitous cabbage. It results in a similar product, with a slightly sweeter taste. Kohlrabi kraut, like sauerkraut, can be made in small or large batches — just follow the ratio of two per cent salt to the total weight of the vegetables. Use a bit less salt in the winter when the cooler temperatures slow the fermentation and a bit more salt in the summer when warmer temperatures tend to speed things up.
3 large kohlrabi, peeled
1-2 apples (optional), peeled and cored
sea salt or kosher salt
Before beginning, ensure you have a large food-safe container (ceramic or glass) for the kraut, allowing headroom for the swelling of the mixture during fermentation. Weigh the kohlrabi (and the apple, if using,) and then weigh out two per cent of the kohlrabi’s weight in salt.
Using a mandolin or a sharp knife, julienne the kohlrabi and the apple and place into a clean large bowl. With clean hands, massage the salt into the julienned pieces. Let the mixture rest for a few minutes for juices to develop, then mix again. Transfer the young kraut to the foodsafe container or fermentation crock, and pack tightly, so the shreds are completely covered. Do not worry if the kraut is not completely covered at first — the salt will continue to draw water from the kohlrabi, creating more brine. It may also be necessary to weigh the kraut down in order to keep it submerged. If after a day, the kraut is still not completely covered, whip up a two per cent salt brine (1gram of salt to 50 millilitres of water) and pour over to cover. Cover the container and place in a cool environment (under 18C is preferable), checking the container every few days for mould or scum. Skim off scum, if necessary. The rate at which the kraut ferments depends on the ambient temperature: higher temperatures increase the rate, hastening the production of lactic acid, souring the kraut more quickly. Taste often, until a desirable flavour is achieved. Transfer the kraut to the fridge or to cold storage. It will continue to ferment slowly and develop flavour.
Typically mustard seeds are soaked in vinegar, wine or beer, to produce the spicy condiment. By using mature sauerkraut brine as a replacement, this live mustard incorporates lactic acid bacteria, providing additional health benefits as well as extending its shelf life.
1 cup yellow mustard seeds or a mix of yellow and brown (brown adds more heat)
1 1/3 to 1½ cups mature sauerkraut brine (or any lactofermented vegetable brine)
3 tablespoons raw honey, or maple syrup
sea salt or kosher salt, to taste
Combine all the ingredients, except the salt, in a large glass jar (12 ounces or larger) and stir to combine. Loosely cover the jar with a lid or cheesecloth, and leave to ferment at room temperature for 2 to 3 days. Check the flavour of the mustard. The tanginess will vary depending on the initial lactic acid content of the brine and the temperature of the jar’s location. Ferment longer for more acidity, checking periodically, until satisfied. Pulse with a hand-blender or food processor to achieve a desirably textured finished product and season with salt to taste. Store the mustard in the refridgerator. The mustard will last for months and the heat will mellow over time.