Fermented Black Chestnuts

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Photo by Evan Sung
Fresh, sweet chestnuts are at their peak in the early fall.

The Noma Guide to Fermentation(Artisan Books, 2018) by Rene Redzepi and David Zilber is perfect for every experience level of readers interested in fermentation and recipes that require fermented ingredients. With 500 step-by-step photographs that illuminate the process behind fermentation and more than 100 different recipes perfect for everyday practical application, ordered from simple to complicated, everyone is sure to find something they enjoy.The goal of this book was to document the hard work completed by every involved with Noma and to make the knowledge and recipes accessible to all people, especially those outside of the restaurant world.

Makes 1 kilogram


  • 1 kilogram fresh chestnuts in the shell

Fresh, sweet chestnuts are at their peak in the early fall. They contain a fair amount of water, and although they have a shell to keep that moisture in, like garlic, they should be wrapped in foil or plastic for more moisture retention. At Noma, we’ve found that chestnuts taste far more interesting when they’re not fully blackened. Held at 60 degrees Celsius/140 degrees Fahrenheit, the chestnuts take about 4 weeks to mature to the ideal point. The flavor is akin to grape must, with notes of plums and dried fruit. Any chalkiness you might associate with raw chestnuts gives way to a pleasantly meaty texture with a bit of snap. Past the fourth week, deep caramel tones set in but the flavor becomes a bit one-dimensional.

Arrange the chestnuts in a single layer in a vacuum bag. They’ll need to sit flat in your fermentation chamber, so if it looks like your chamber might be too small, remove a few chestnuts. Seal the bag on maximum suction. You can also use a large zip-top bag and squeeze all the air out by placing the chestnuts in the bag, then slowly lowering it into a large tub of water, stopping a few centimeters from the top (you may need to pull from the bottom of the bag to counteract the chestnuts’ buoyancy). The pressure of the water will force the air out. Seal it shut and you’ll have an effective, albeit imperfect, vacuum.

Place the chestnuts in the fermentation chamber. If you’re using an electric rice cooker or slow cooker, remember to raise the chestnuts off the bottom with a plate, wire rack, or bamboo mat. Close the chamber and set it to 60 degrees Celsius/140 degrees Fahrenheit, or seal the cooker and turn it to the “keep warm” setting.

Leave the chestnuts in the chamber or cooker for 4 weeks. Slit one open to taste and decide whether you want to go a little longer. Once they’ve blackened to your liking, keep them in the shell until you want to use them. Store in a sealed container in the fridge if you plan to use them within a week, or freeze for longer storage.

Suggested Use

Stuffed Pasta

With very little modification, black chestnuts can be turned into an unbelievable filling for pasta. Start by chopping 350 grams peeled black chestnuts into thin slivers. In a medium sauté pan, heat 100 grams butter until it begins to foam. Throw the chestnuts in and sauté for a few minutes before adding 250 grams good chicken stock. Cook at a simmer beneath a round of parchment paper until the chestnuts are fairly tender. At that point, transfer the contents of the pot to a blender and puree the mixture until it’s silky smooth (depending on your blender, it may need a touch of water to help it spin). Season the puree with salt and mace or nutmeg. Pipe it onto fresh pasta and form your preferred stuffed shape: cappelletti, agnolotti, tortellini, ravioli. And to take things to an entirely new dimension, glaze your pasta with the Lacto Koji Butter Sauce after it’s cooked.

More from The Noma Guide to Fermentation:

Excerpted from Foundations of Flavor: The Noma Guide to Fermentationby Rene Redzepi and David Zilber (Artisan Books). Copyright © 2018. Photographs by Evan Sung. Illustrations by Paula Troxler.