DIY Covered Speed Rack Fermentation Chamber

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Photo by Evan Sung

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.

For this fermentation chamber, you’ll need:

A speed rack:

The bones of your chamber. Speed racks are used in restaurants to hold trays of ingredients or food coming out of the oven. They’re made of lightweight but sturdy aluminum and are equipped with rails onto which you slide sheet pans or gastro/hotel pans. They come in varying heights, ranging from 1 to 1.75 meters. Look for one that comes with a heavy plastic
or vinyl cover with zippers running up two sides. The cover will retain heat and humidity, and the zippers allow easy access to the interior. You’ll also need a few sheet pans that are the correct size for the rack; the style and quantity will depend on which ferments you choose to make.

A small space heater:

The kind you might use to keep your feet warm underneath your desk. If the heater is equipped with a fan, all the better; if not, buy a small simple fan.

A temperature controller, such as a PID (proportional-integral-derivative) or thermostat:

This will adjust the temperature of the chamber as it varies according to external influences. You want a prewired version that you can plug a heater directly into. It’s a specialized bit of gear, but it’s not complicated or expensive. It will include a probe that you set either in the chamber to measure interior temperature, or into the ferment itself, such as when you’re making koji.

A small humidifier (only when making koji):

The type you’d put in a child’s room to help with a stuffy nose. Plus, a simple hygrometer to gauge humidity; it will look a bit like an oven thermometer. Or use a humidistat, which functions much like a thermostat. While slightly more expensive, it will simplify things by regulating the humidity in the chamber for you.

  1. Assemble the speed rack and slide one or two sheet pans into the lower shelves. Space them to allow enough room for your heater, humidifier, and hygrometer or humidistat (and fan, if the heater doesn’t have one built in) to sit without interfering with one another. Place the devices on a sheet pan and snake the cords out from the bottom of the rack.
  2. You’ll want to keep your temperature controller outside the chamber. Plug it in and set it
    to the correct temperature, following the manufacturer’s instructions; for the ferments in this book, that will be either 30 degrees Celsius/86 degrees Fahrenheit or 60 degrees Celsius/140 degrees Fahrenheit. Run the temperature probe into the chamber. Plug the heater into the temperature controller.
  3. Arrange the hygrometer or humidistat sensor so it won’t be in the direct flow of the steam from the humidifier. Fill the humidifier with water, plug it in, and set it to medium. Note that we’re clearly dealing with a lot of electrical cords, so use a properly rated power strip.
  4. Pull the plastic cover over the speed rack and zip it up. Air will be able to enter the chamber from the bottom, which is what you need for most of the ferments. When fermenting at 60 degrees Celsius/140 degrees Fahrenheit, you may want to add an extra layer of insulation underneath or on top of the plastic cover. A clean cotton or wool blanket will do the trick nicely.
  5. Close the cover to bring your chamber up to the desired temperature and humidity.
    If you don’t have a humidistat, you’ll adjust humidity by checking the level on your hygrometer and then dialing the humidifier setting up or down. The temperature controller will take care of temperature for you.
  6. Add your ferments. Keep an eye on the temperature controller to make sure it’s turning the heater on and off when the temperature dips or rises. You may see a drift of a degree or two above or below your desired temperature; that’s normal.

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.