In my last Illinois Times column I reviewed the recently published The Noma Guide to Fermentation. During the past month I have been working my way through several of its recipes. However, I’ve discovered that fermentation is more than merely following a recipe. It’s also about being a good shepherd, providing optimal conditions for microbial growth. Think about it: humans have coevolved over time with millions of bacteria inhabiting our gut. This symbiosis helps us better digest certain foods, and a happy internal microbiome is critical to our physical and emotional well-being.

My first project was butternut squash vinegar. The Noma Guide to Fermentation recommended fermenting for 10 to 14 days then straining the vinegar through cheesecloth and bottling and storing it in the refrigerator. I tasted the vinegar at 10 days; it was mild, but very clean and bright. I used it to season a batch of butternut squash soup I made for an out-of-town cooking event last month. The soup received rave reviews. However, being pressed for time, I had failed to bottle and refrigerate the rest of the fermenting vinegar before I left on my trip. When I returned and bottled my vinegar, I noticed that it had picked up a mild, funky taste and smell that wasn’t there previously. I had fermented it a little too long.

My next project was celery vinegar. Aside from problems with the stringy celery clogging up the juicer, the fermentation went well, and at day 10 all the alcohol taste had vanished and the resultant vinegar retained the taste of fresh celery. It is fragrant and bright tasting. The celery vinegar is now bottled up in my refrigerator, ready to season a soup or be made into vinaigrette.

Encouraged by my success, I am now fermenting my vegetable scraps: kale and broccoli stems, turnip and beet tops and cabbage cores.

The kitchen table in my tiny rental house is beginning to look like a microbiology lab with bubbling jars of soonto-be vinegars and jars and crocks of krauts and kimchi. My next goal is to undertake some more complex projects such as soy sauce and miso. This will require building a fermentation chamber with temperature and humidity controls. With the Thanksgiving and Christmas holidays approaching, I’ve had to move my existing fermentation setup from the kitchen table into the laundry room. Construction of the new fermentation chamber will have to be postponed until the holidays are over.

Anxious to keep my fermentation project going, I thumbed through The Noma Guide to Fermentation looking for another project with a less-elaborate setup. The last chapter in the book is titled “Black Fruits and Vegetables.” The process involves placing a fruit or vegetable in a sealed container and maintaining a constant temperature of 140 F for 6 to 8 weeks. The resultant fruits or vegetables develop a deep black color and acquire a very rich, almost chocolatey sweetness. Lacto-bacteria cannot survive at this temperature so the process is technically not fermentation, but rather a temperature-driven enzymatic transformation. A rice cooker with a “keep warm” setting is an ideal black garlic “incubator.”

I bought a dozen heads of locally grown garlic, sealed them in a Seal-A-Meal bag, and placed the package in my electric rice cooker. The “keep warm” setting of the rice cooker is very close to the required 140 F. Six weeks later my garlic was dark black, had an earthy fragrance, was putty-like in texture and tasted like dark chocolate. Gone was the garlic’s characteristic heat. Also gone was the garlic’s resultant bad breath.

RICE COOKER BLACK GARLIC

Try to find the freshest, moistest heads of garlic. Discard any bruised or moldy sections. If you have a vacuum sealer, package whole heads in a single layer that will fit in your rice cooker. Otherwise seal tightly with two layers of foil. Place a trivet or a few canning jar rings on the bottom of a rice cooker to elevate your garlic package and allow air to circulate beneath. Set the rice cooker on the “keep warm” setting. Inspect the garlic after a week. The skins should look tan and moist. Periodically turn the package over. Allow garlic to blacken for 6 to 8 weeks. When ready, allow the garlic to sit out on the counter overnight to dry out. Then refrigerate if using within a couple weeks or freeze for later use.

Black garlic shouldn’t be substituted for fresh garlic in recipes. It has its own distinctive taste in the same way that balsamic vinegar tastes different from white vinegar. Softer and subtler than fresh garlic, it is best paired with milder-tasting ingredients like mashed potatoes or pureed cauliflower. Because it’s less assertive than fresh garlic, plan on using more cloves. Try mashing a few cloves, blending with a little olive oil, adding a pinch of salt and spreading on a crostini. Combine black garlic and mayonnaise in a food processor to make a quick black garlic aioli to use as a sandwich spread. Save the skins and use them to add flavor to chicken stock. Or make this buttermilk “ranch” dressing.

BLACK GARLIC BUTTERMILK DRESSING

Try this as a veggie dip or as sauce for roast chicken or lamb.

4 medium heads black garlic, left whole but peeled

1 cup buttermilk

1 tablespoon champagne vinegar

1½ teaspoon salt

3/4 teaspoon black pepper

1 cup olive or grapeseed oil

Peel the garlic cloves.

Put everything in a blender but the oil and puree. With the blender running, slowly stream in the oil.