The blooms were out when I arrived in June, and faded through July. The berries, I knew, wouldn’t ripen till fall. But in August, at a old castle in Northwest Zealand, I found towering elder trees brushed with green fruit, gathered in fronds the span of my hand or more. Unripe berries means capers. Capers means delicious. The late trainride back to Copenhagen goes slowly. I itch to get them brining.
Lacto-fermentation is one of the simplest wild ferments. All it takes is some produce and a bit of salt, and the lactic bacteria do the rest. The little organisms transform sugars into lactic acid – one of the same processes involved in turning milk into yoghurt, certain cheeses, and other dairy products. The result with vegetables and fruits is a complex, gentle acidity and a satisfying depth of flavour. It is a richly live food with great benefits for intestinal micro-culture, and thus for the whole body. Indeed, some foods that contain harmful toxins – like unripe elderberries – can be made edible not only through the application of heat but also through fermentation.
The next morning, I am up and shucking. The berries are luminous and firm, a fan of pebbles or runt peas.
Once the stalks are picked clean, I seal the berries in a vacuum bag with five percent salt by weight. The average salt ratio for lactofermentation is around two percent, but I want to brine these puppies for a good long while, so I keep it high.
We love our vacuum packer at the lab, but you certainly don’t need one to get your lactofermentation on. The most common way, in fact, is to submerge whatever you’re fermenting under its own brine. Packing cabbage or whatever else into a crock with salt draws liquid out of the plants, which keeps them covered and prevents aerobic distractions like mould and flies. A good healthy lactoferment will come to be dominated by lactic bacteria, keeping anything else from getting a foodhold on your food.
And I label the package and leave it in the basement for three weeks.
In the meantime, we’re juicing kilos and kilos of fruits and vegetables to make vinegar. Juicing means lots of leftover pulp; ‘waste’ means material for experimentation. I take some of each – apple, pear, carrot, strawberry, peach – two-percent-salt it, seal it and let it lacto-ferment a couple days until the bags puff up. Some don’t do much, like the carrot; but others go from bland, faded versions of their true selves to punchy, salty-sour characters waiting to break into the ring. Especially the peach – the next day I enjoy it for breakfast, a big dollop on top of some yoghurt with caraway, mustard seed, birch syrup and wood sorrel.
And then, in mid-September, the day comes to open the brining elderberries. They have turned dark green, and soft; small bubbles filter up through the bag. I open it and an overwhelming perfume of elderflower surges out. I could eat them all now. But six more weeks packed in vinegar will make them truly extraordinary. I reluctantly fill the bag with raw apple vinegar, seal it, and put it back downstairs.
In the meantime, huge branches of sea buckthorn have found their way onto the boat. I pick the berries, rinse them off, salt, seal, and start the process over. They’ve been brining downstairs for a couple weeks now, and every day their orange shades deepen.
Josh Evans is a regular contributor for Diaforlife.
He recently graduated from Yale University and has moved to Copenhagen to work at the Nordic Food Lab.
You can read more about Josh, his adventures and fabulous cooking on: hearthstrung.wordpress.com