My fellow communards have rarely been as enthusiastic about any of my ferments as they were the night I first served sauerrüben. They went on about it as if it were a rich chocolate desert. Sandor Katz, Wild Fermentation.
Sauerrüben, or lacto-fermented turnips, are common in some parts of Germany and Poland, though not quite as ubiquitous as sauerkraut. Like sauerkraut they are a dry-brined ferment. They taste delicious as a condiment on a sandwich or sitting alongside some cooked meat. Turnips contain a lot of water and are thus easy to dry-brine. They are also slightly sweeter than cabbage thus making a very pleasing and easy to prepare ferment. I added radishes which gives them a pleasing, pink blush. You can add what ever you like – onions, garlic, fennel seeds etc. For a more in-depth analysis of dry-brined ferments see my post on sauerkraut.
Wash, but do not peel, the turnips. With a sharp knife, mandolin, grater or food processor, shred the turnips. If you are using radishes pulse them in the food processor – they are a bit too small to shred easily.
Sprinkle some sea-salt over the chopped vegetables and leave to rest for five to ten minutes. After this time squeeze as much of the juices out of the turnips as possible. Taste the mixture. I know this can be hard to gage if you’ve never tried dry-fermenting vegetables. If it helps, current orthodoxy is that for a dry-brine ferment you only need 2% of total weight. So for every 1 kg of vegetable used expect to use approx. 20 gr of salt equivalent to one tbsp. of salt. It doesn’t need to be more or it will be too saline and discourage the growth of even beneficial organisms – the very things that make a successful ferment. If it’s too low the fermentation might not work.
Push the shredded turnips under their own brined juice, seal the lid and leave on the kitchen counter for two – three days. In the first couple of days the heterofermentative LABs (L.mesenteroids) will be the most active. These early micro-organisms are responsible for 85% of the total lactic acid in the ferment. They will also be busy secreting large amounts of carbon, alcohol and acetic acid alongside the lactic acid. Because of L.mesenteroids’ early activity expect to see your ferment bubbling away in the first couple of day. It will look very alive and merry.
After three to four days the environment will have turned too acidic for L.mesenteroids and they will be replaced by the more acid-tolerant LABs, Lactobacillus plantarum. At this stage the ferment will stop producing huge amounts of carbon and will become more stable. It is around this stage that you can place your jar in the fridge. You can your sauerrüben at any stage. The longer it is left the maturer and more developed it will taste and the more intense the flavours and colours will become.