Yeast

brewers yeast? a key ingredient for some scrumptious bread

you can buy it at places they sell wine accessories, cellar, etc...

"Top-Fermenting Yeast
Ale yeast strains are best used at temperatures ranging from 10 to 25°C, though some strains will not actively ferment below 12°C (33). Ale yeasts are generally regarded as top-fermenting yeasts since they rise to the surface during fermentation, creating a very thick, rich yeast head. That is why the term "top-fermenting" is associated with ale yeasts. Fermentation by ale yeasts at these relatively warmer temperatures produces a beer high in esters, which many regard as a distinctive character of ale beers.

Top-fermenting yeasts are used for brewing ales, porters, stouts, Altbier, Kölsch, and wheat beers.

Bottom-Fermenting Yeast
Lager yeast strains are best used at temperatures ranging from 7 to 15°C. At these temperatures, lager yeasts grow less rapidly than ale yeasts, and with less surface foam they tend to settle out to the bottom of the fermenter as fermentation nears completion. This is why they are often referred to as "bottom" yeasts. The final flavour of the beer will depend a great deal on the strain of lager yeast and the temperatures at which it was fermented.

Some of the lager styles made from bottom-fermenting yeasts are Pilsners, Dortmunders, Märzen, Bocks, and American malt liquors."

Awsome, thanks, ++ Karma.

oh and there are really only two types of yeast, Bakers yeast (Dry, found at the grocery store) or brewers yeast (Dry or Wet, purchased online or at brewing hobby stores).  From experience brewing my own beer, probably 10 batches 5 gallons each, the most important thing is cleaning everything completely before starting, like really cleaning it well.  Bacteria and leftover yeast from previous batches really fuck up 5 gallons of beer.  Beer that taste exactly like soy sauce is hard to drink heavily haha.