Lacto-fermented blueberries are one of the easiest and more versatile products in this chapter. They need no prep other than a quick rinse, and once they’re done you’ll find heaps of simple uses for them: Toss some onto your morning yogurt and granola, or add them to a smoothie, or puree the fruit and juices to make a salty-sweet coulis to be drizzled over ice cream or fresh cheese. Fermented blueberries freeze well and thaw quickly, making them easy to keep on hand at all times.
NOTE: The in-depth instructions for Lacto Plums in The Noma Guide to Fermentation serve as a template for all the lactic fermentation recipes in this chapter.
1 kilogram blueberries
20 grams non-iodized salt
If fermenting in a vacuum bag: Place the blueberries and salt in the vacuum bag and toss to mix the contents thoroughly. Do your best to arrange the berries in a single layer, then seal the bag on maximum suction. If you’re gentle with them, the blueberries will retain their shape through the fermentation. Be sure to seal the bag as close to the opening as possible, leaving headroom that will allow you to cut open the bag to vent any gas that accumulates and then reseal it.
If fermenting in a jar or crock: Mix the salt and blueberries together in a bowl, then transfer them to the fermentation vessel, making sure to scrape all the salt from the bowl into the container, and press the mixture down with a weight. (A heavy-duty zip-top bag filled with water will do the trick.) Cover the jar or crock with a lid, but don’t seal it so tightly that gas can’t escape.
Ferment the blueberries in a warm place until they have soured slightly but still have their sweet, fruity perfume. This should take 4 to 5 days at 28°C/82°F, or a few days longer at room temperature, but you should start taste-testing after the first few days. If you’re fermenting in a vacuum-sealed bag, you’ll also need to “burp” the bag whenever it balloons up. Cut a corner open, release the gas, taste the blueberries, and reseal the bag.
Once the blueberries have reached your desired level of sourness, carefully remove them from the bag or fermentation vessel, and strain the juice through a fine-mesh sieve. The blueberries and their juice can be stored in separate containers in the refrigerator for a few days without a noticeable change in flavor. To prevent further fermentation, you can also freeze them separately in vacuum-sealed bags or zip-top freezer bags with the air removed.
Fermented blueberries play a big part in our savory kitchen at Noma, but of course, most people think of blueberries as a sweet treat or a topping for yogurt in the morning. Fermented blueberries boost a simple breakfast into more sophisticated territory. A big scoop of plain yogurt, a spoonful of lacto blue-berries, and a drizzle of honey will easily get you through until lunch.
Lacto Blueberry Seasoning Paste
The pulp of lacto-fermented blueberries, blended smooth and passed through a sieve, makes for a tart, savory condiment for vegetables and meat alike. It’s spectacular brushed on fresh corn on the cob with a bit of butter, or tossed with roasted beets. Paint barbecued ribs or pork chops with lacto blueberry paste before or after grilling, or make a barbecue sauce by substituting it for tomato paste or ketchup in your favorite recipe.
Excerpted from The Noma Guide to Fermentation by René Redzepi and David Zilber (Artisan Books). Copyright © 2018.
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