“I read today that crab grass seeds can be harvested and used as flour.”
Can they be fermented?
Yes.
http://www.eattheweeds.com/crabgrass-digitaria-sanguinalis-2/
“Crabgrass seed can be used as a flour, couscous or as a grain, such as in porridge or fermented for use in beer making.”
Our Lord is Good!