A strange word which seems like it’s only used in Oaxaca guarape comes from “guarapo” which means sugar cane juice and, in some cases, fermented sugar cane juice. The non alcoholic version is wide spread in central and south America, a staple of local markets and juice bars. I’ve started to see it in the United States as well, it’s incredibly refreshing and an incredible base for classic Caribbean cocktails.
So, guarape was most likely borrowed from the sugar cane world for a similar substance in the mezcal world. Carmen Vasquez told me that it is a very localized term used by few to refer to the fermented agave mash. It’s also used occasionally for lightly fermented juices, both in Oaxaca and the Caribbean.