posted by Josh Evans
Part sourdough starter, part pickling machine, nuka is a versatile Japanese technique for fermenting any and all sorts of vegetable. Traditionally, the Japanese mix the rice bran left over from polished white rice with water and salt, as well as beer and/or sake, to form a stiff paste. A new vegetable is pressed into the paste each day until it tastes sufficiently sour, at which point the nuka is ready for full use.
We became interested in nuka from Sandor Katz' The Art of Fermentation, and we wanted to explore other versions beyond rice. We've landed on oat bran as an exciting alternate, for its sweet and nutty flavour, and a dark beer for big body (we found ourselves with plenty of the Herlev Organic Stout, which we also used for brining). 900g oat bran, 500g beer, 40g water, and 29g salt (2%).
We started our nuka with a nub of carrot. We rubbed it with salt to abrade its skin, then buried it beneath the bran paste and left it for one day covered with a cloth and tied with string. The next day, we replaced the carrot with a kale stem, and the next, a heart of cabbage. Adding a new vegetable each day contributes fresh lactobacilli, allowing the nuka to become fully enculturated and preventing the growth of moulds. After the third day, our vegetables began to taste mildly tart, barely softening, springy.
Then we started the full-on pickling machine, packing a 5-litre container with layers of peeled jerusalem artichokes and active nuka.
After one day, the sunchokes were slightly soft and acidic, but we left them in for a few more days – we were after the big flavour of furu-zuke, 'old pickles'.
And we met a whole new character – lightly sweet from the oats, full and deep from the beer, sour and lactic from the bateria, yielding to the teeth but with crunch, like marinated daikon radish. The unmistakeable flavour of the sunchoke. And a hint of fizz – I wonder if there might even be some yeasts in there, from the beer perhaps.
We packed them under vacuum to bring with us to Terra Madre, to share with some friends who were exploring other pickling methods on jerusalem artichokes.
Next up: nuka'd plums.