My grandfather used to brew root beer in his basement. He had about 100 bottles in a rack. Every once in a while one of these bottles would explode. I think this was different from the root beer you buy in the store. It was alcoholic.

I'll go out on a limb here and guess that in olden times, they stored their brews in containers that were not 100.00 percent airtight. So the alcohol would gradually evaporate out of the liquid and escape. So, "new" ale had a higher alcohol content.

My brain is old but I seem to have memories back there somewhere of reading literature, more than once, where someone got real loaded drinking new ale.