Saccharomyces cerevisiae is a top fermenting yeast and S. uuvarum is a bottom fermenting yeast. The latter is used to make ales and lager beers. The carbon dioxide is allowed to escape and is a major byproduct of brewing. The mixture is allowed to ferment for 7-12 days at cool temperatures. The resultant liquid is tranferred and allowed to age for 2-3 weeks.
Proteins precipitate out and some other chemical modifications take place.
In the U.S., most of the beers are pasteurized or micropore filtered to remove yeasts. The beer is usually carbonated. Sake Sake is made from rice and is a traditional beverage in Japan. It is a fermented grain beverage. Aspergillus oryzae is used to convert the starch to sugar and then yeast added.