Make your own fermented viili | MNN – Mother Nature Network

Make your own fermented viili | MNN – Mother Nature Network

Last weekend, I entered the world of fermented food. Amanda Feifer O’Brien, the fermentation evangelist I interviewed back in January, got me started at her Basics of Fermentation class.

After giving the class some basics about the importance of bacteria in our bodies and how we’re messing up our body’s ecosystems by eradicating bacteria through the overuse of antibiotics and antibacterial cleaning products, Amanda got down to business.

I’ve already made my first two batches of viili, and I thought I’d share what I’ve learned about this Finnish dairy product, which is similar to yogurt. I can’t believe how easy it is to make. It takes one minute each morning to take a bit of the prepared viilli and use it as a culture for the next day’s batch.


  • 1 cup of pasteurized milk. (I tried both 1% and whole milk. The whole milk created a much more pleasant product. The photo at the top is my viili made with whole milk.)
  • 1 heaping teaspoon of prepared viili


  • Take the prepared viili and spread it all around the bottom and half way up the sides of the bowl you’ll be making it in.
  • Fill the bowl with milk up to the line on the side where the spread viili is. Depending on the size of your bowl, it could be one cup of milk. It also could be more or less.
  • Cover the bowl with a clean towel and leave it out at room temperature (65 – 75 degrees) for about 24 hours.
  • It will be set like jelly when it’s done.
  • Before you eat it, pull out a tablespoon or so to reculture the next bowl. You could, of course, reculture several bowls, depending on how many you’ll need for the next day.
  • If you can’t eat your viili the next day, it will keep in the refrigerator up to 10 days, and you can use it to reculture other bowls during that time.

I have to admit, I was very skeptical about the safety of a milk product that had set out on my kitchen counter for an entire day. I asked Amanda to explain why it is that viili doesn’t go bad at room temperature. This is what she told me.

The culture preserves the milk. The milk feeds the bacteria which thrive and, through their digestion, create a more acidic environment that preserves the milk while creating an inhospitable environment for less friendly bacteria. I know that this goes against traditional American notions, but I swear, it works and works well.

Sandor Katz mentioned something interesting in the “Art of Fermentation.” People have milked animals for a long time. Refrigeration hasn’t existed for a long time. So basically fermented milk is the rule, historically speaking, and fresh milk consumption is a blip on the radar screen.
Also, viili is the exact same process as making yogurt, only you don’t need a higher temperature to do it. The higher temperature in yogurt-making creates the perfect environment for those particular bacteria to thrive and multiply and do the work of preservation. The viili bacteria don’t need a high temperature to thrive, which is why it’s easier to make.

Her explanation, combined with the fact that I ate the viili I made at home and didn’t get sick, is enough to convince me that this is safe.

If you’re interested in making your own viili, fresh cultures can be ordered from GEM Cultures for $14.

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