So, I made some beet kvass and convinced my husband to drink some. He likes beets, so he actually likes it much better than I do.

Problem is, 12-24 hours after he drinks it, he gets terrible stomach aches and nausea. Now, he eats lots of yogurt, raw cheeses and raw milk, but he was a sugar/carb addict for years. We've tried to pinpoint the source of his problems, and it seems to always come back to the kvass.

I searched the internet about this and just found this: Re: Beet Kvass Question

But I fear my husband will think the "it's cleaning out your liver" line is just hokey.

Someone on that thread mentions charcoal caps. We have some of those, and my husband believes that they work. So, should we try a sequence of kvass / charcoal? Say, take one charcoal 2 hours after drinking 6 oz. of kvass?

I should also mention that I think my husband drinks about 8 oz. of kvass at a time, and it's pretty syrupy. I think, after searching the internet about this problem this morning, that it could stand to be diluted a bit. So maybe that's a part of the problem.

Given that my husband does have a problem with stones, and he likes beets, I don't want to give up on the kvass.

I was also thinking of doing a secondary ferment with the kvass we have. Since it likely needs to be diluted anyways, just put some apple/ginger/whatever juice in some smaller jars and let them sit a few more days. But then we still have to deal with whatever the fermentation is doing to his gut.

So, what do you guys think? Is it possible the culprit is the kvass? Is taking charcoal worth it for long-term health?