Beer!

Quick Questions:
Standard etymologies vary in finding the origin of "beer, bier, beor, etc".

Lately, it has been suggested that beer is from Middle "monastic" Latin,
biber, from Classical Latin, bibere (to drink, sometimes alcohol). The beer
word itself appears to occur first in western Germanic.

Some claim that an origin for <beer> may be found in the "barley" and "brew"
words.

But the most serious objection I have heard is that there are no examples of
early post-Classical L. <biber> meaning beer or any alcoholic beverage.

On the web, i've found a genealogical that claims that:
"Biermann, it has been confirmed that it was known in 1349 meaning a person
who sells or handles beer, but does not necessarily refer to it as meaning
one who makes beer....Biermann... was originally rendered in Latin documents
in the form of Biber, which means to drink."

I also found a "Vademecum in opus Saxonis" that lists "biber-is f. (<
inf..bibere) = potio" but seems to say that it does not appear in Saxo.

Does anyone know of an appearance of <biber> in early middle age texts that
could mean beer or something like it that might justify the <biber> > <bier>
connection?

Also, how extensive is the "brew" word in IE languages? It appears that the
word is also taken as being direct from *PIE to Germanic. In Greek, I see
<brusis>, bubbling up; <brutos, bruton>, "fermented beverage made from
barley, beer"; cf., <brutea or brutia> "refuse of olives or grapes after
pressing,... poma." But what is the Latin cognate and how is this
development in Greek and Germanic explained?
Regards,
Steve Long