I was exploring Toronto's St. Lawrence market this summer. Ambling past a Ukrainian deli, I came upon a bottle marked “KBAC”. Suspicious, I called over a Slavic friend who happened to be there and asked her to read it to me. “Kvass”, she said.
I've heard of that! in a book I once read about Mennonite foods. It was some fermented drink involving bread. It sounded weird (even weirder since I was confusing it with kefir, fermented milk.) Of course I bought it.
I've heard kvass described as low alcohol beer. I think it is more like pop. It has a distinctive flavor and yet reminds me of something familiar. I haven't yet put my finger on it, maybe plum.
Researching, I find that it comes in bread and beet varieties. It has been brewed for over a thousand years (though I wonder if the traditional recipes had sugar for the yeast.) Kvass is enjoying a resurgence in Russia and Ukraine lately. Coca-cola has developed a brand and a monastery near Moscow has started bottling its traditional recipe. Modern enthusiasts rave about its probiotics, which would have been important in the days before clean water.
You can make it yourself. It is basically rye toast tea. I have been trying a few batches at home based on Angelina's recipe. She flavors it with raisins. Others suggest lemon or mint. (Both inhibit bacteria growth.) I tried a batch with raisins, then with raisins and lemon (crushing the lemon and careful to capture the oils from the zest.) My current batch has raisin, mint and lemon.
Compared to Angelina, I make batches a quarter the size, only 2.5 liters. Remember, it is alive and will only last 2-5 days. Where Angelina emphasizes the need to burn your toast, I discovered that there is such a thing as too burnt. You want to see some blackening, but no charcoal. Mine has 2/3 the sugar. You can recover 20% of the liquid if you put the bread in a colander after scooping it from the pot.