When I met my boyfriend in college I bought him a beer making kit for his birthday. I thought he needed a hobby. Of course you can make wine as well with it. We have been making apple wine lately. Some batches come out ok, but we are trying to tweek it because most of them are too bitter.
One day he decided to try and make Guiness with it. I asked him to put it out on the patio just in case, but as you guessed it, he didn't. He kept the container in the kitchen up on the countertop. When I woke up the next morning the house reaked of Guiness. I went into the kitchen to find that the guiness had exploded and everything including the ceiling was covered with the stuff.
I am happy to report that we haven't had any explosions since, knock on wood.