This, my friends, is a widely accepted possible method (by archaeologists) of how our modern brewing evolved! I have done research on primitive fermenting, and this matches up to what I've found. (ie open fermentation in wooden trough burried in the ground, filtered using plant material, and natural yeast and/or bacteria cultures to ferment) Funny thing is the research I did centered around mead and "ancient beers" from northern Europe (Scotland, Wales, Norway, Holland, Etc). Yeay for banana brewery!!
Not to be a know-it-all, but the yellow "gas can" is actually a water canister. Here our's are blue, clear, and brown.