“Would would happen if…?” is a question that I ask constantly – not just in food, but in all areas of life. In July, I was in the midst of exploring obsessions for coffee and for vinegar. It was at that point when I wondered “What would happen if coffee could be fermented?” Now, knowing basic chemistry, I knew that coffee all by its lonesome would likely never ferment. It was hot water extracting flavors and oils from beans. There was no sugar to convert in coffee, at least in my coffee there was not. When I made coffee for my mother-in-law, whose coffee resembles a toaster strudel more than coffee, I realized that coffee dissolves sugar and that the resulting compound could be fermented.

At that point, I had done some research to see if coffee vinegar had been tried before to results, but I did see that people were making coffee kombucha in the same way that I was planning on trying coffee vinegar. It seemed almost natural to try them side-by-side to determine which would work better.

I had vinegar mothers galore at this point, so I brewed a pot of the Kenya from Alterra took a pint of it, added a tablespoon of sugar and allowed it to cool and dissolve. Once it was at room temperature, I added an active mother, covered the jar with cheesecloth and put it up. Two weeks later, I added the same amount of sugared coffee (still Kenya) and let the mixture ferment for three months. For Kombucha, I had no starter, so I made one using live Kombucha off the shelf, tea and sugar.

The method is quick. Simply brew a pot of tea, make a cup of tea sweetened with a tablespoon of sugar, and add it to the bottle of unflavored live kombucha. Two weeks later, I had something that looked like a vinegar mother. I added this mother-like blob to a pint of sweetened coffee. I allowed the coffee kombucha to ferment for a month – tasting periodically.


As I tasted the vinegar and kombucha, I noticed an evolution. In the beginning, the flavors were simply the same as the coffee. As the fermentation began to occur, aromas of leather and significant earthiness were really prevalent. Once I bottled the fizzy, fermented coffee kombucha, I tasted again and it was sour from the fermentation, the bitterness in the coffee was still there, but was muted and left were the secondary flavors of the coffee. It was delicious over ice.


The vinegar took much longer to ferment to a point where it was sour enough to qualify, but similar aromas and flavors happened during fermentation. As I bottled the vinegar, I tasted it and it ended up being substantially different than the kombucha. The coffee flavors were concentrated, but the whole mixture had developed a wild, fermented flavor that was more complex than regular vinegar. It was bitter and sour, and while to some, that may sound disgusting, to me, it opened up a lot of avenues.

Personally, I think that balsamic vinegar, or what is sold as balsamic vinegar, is overused – especially in the fall. This vinegar seems to be the polar opposite. There is no sweetness to it, but the complexity and bitterness would go equally well with many of the foods – pumpkin, squash, carrots – typically paired with the syrupy vinegar in the fall. I had my eye from early in the process when I acquired a fair bit of country ham on a first use and that would be a modification of red-eye gravy.


Early on Sunday morning, I sliced two thin rashers of Benton’s ham and let the fat render in a pan. When the ham was sufficiently cooked, I removed it and poured a fair bit of the coffee vinegar in with the rendered country ham fat. The globules of fat were beautifully set off from the acidic, sour coffee vinegar. After reducing and whisking, I poured the new red-eye gravy over steel cut oats, raw apple, and the Benton’s ham for a hot, delicious breakfast outside on a cold day.


The sour and bitter flavors were great with the saltiness of the ham and the sweetness of the apple. It was the answer of my initial question, “What would happen if…?” The answer is that, first, it can be done and, second, if you do it right and find a good use for it, it will be delicious.