If you ask a person. What is beer?
They will normally reply to you "Of course I know that. It is Malt, Hops, Yeast and Water". Some will refer this to "German Beer Purity Law" from 1516 (Reinheitsgebot).
That is true. Still in the Reinheitsgebot yeast is not mention. Because they did not know about it.
Reinheitsgebot definition is not directly correct. The reason for the law was more or less protectionism. And in England some century ago. In England there was difference between beer (beer with hops) and ale (beer without hops).
A few would say it is "fermented grains". That is more correct. But to be more specific.
"Beer is an alcoholic, fermented, not distilled drink made of starch or sugary subjects." [1]
So here you have it.
And then it is also logic that sake (japanese rice wine) is also beer. There are some modification here too. Since some sake included distilled additives. Then it is more like an drink.
You can expect that many will say. "Sake is not beer, if so, thats a new definition. Since I've never heard about it".
If you think sake are beer is an new definition. I will correct you. This information is from 1800. "Beer like styles at different nations ... the Japanese beer or rice wine, Saké is perfect." [2]
And some beer brewery also brew sake. In Japan it was opposite, sake brewery have started to brew beer.
But it is more, Aca an Maize Beer from Peru, Pombe an Sorghum beer from Africa, Sango-lo an rice beer from china [3] and so on.
So now you know. Beer is beer, but some you did not think was beer, is beer.
[1] "Øl er en alkoholholdig, gjæret, udestilleret Drik fremstillet af Stivelse eller sukkerholdige Emner." p. 3
Om øllets og dets udvikling fra oldtid til nutid
Dr. Olav Johan-Olsen
Frydenlunds Bryggeri
Kristiania (Oslo)
MDCCC (1800)
[2] "Øllignende Drikke hos Forskjellige Folkeslag ... Japanernes Øl eller risvin, Saké er den fuldkomneste." p. 23
Om øllets og dets udvikling fra oldtid til nutid
Dr. Olav Johan-Olsen
Frydenlunds Bryggeri
Kristiania (Oslo)
MDCCC (1800)
[3] Brewing Yeast & Fermentation
Chris Boulton & David Quian
2001