well, I don't know how to explain it, lol. I'm not good at describing how things taste. It's not like beer, it smells and tastes much softer, while beer is usually bitter. And, if you happen to find some drink named "kvass" in your general store- it wouldn't be natural kvass, and it will taste very different. Those drinks are made of some concentrated chemical stuff and doesn't have anything in common with natural kvass. I can only advice you to try making it yourself, it's simple. But home-made kvass is usually poorly filtered, and looks disgusting But it tastes almost as good as the one from brewing factory.