Brewer's yeast are like any domesticated plant or animal. That is, they have been carefully selected over hundreds of years to exhibit those characters that the brewers most desired. For beer, that means that they give a relatively "clean" flavor without the sour and off-flavors made by wild yeast. There are basically two broad categories of brewer's yeast - ale yeast and lager yeast. There are many different strains within these two categories. At Live Oak we use three different strains of yeast for our four beers. We use a lager yeast in the Pilz and the Marzen, an ale yeast in the Pale Ale and a very special ale yeast in the HefeWeizen. Ale yeast tend to give a more complex flavor to beer. Thus, ales exhibit a bit of fruitiness and sometimes a even a buttery note in their flavor and aroma. They ferment best at temperatures around 60 - 70°F. You might pick out a hint of fruitiness in the nose of our Pale Ale.
Conversely, lager yeast have been selected to give an extremely clean flavor to beer - you might say "no flavor". Lager yeast ferment at cooler temperatures (45 - 55°F) than ale yeast. This is thought to play a role in their relatively clean flavor profile. Lager yeast make the subtle flavor of the malt and delicate hop character all the more accessible in lager beers. The typical German beer is a lager. Our Pilz and Marzen are excellent examples of the subtle complexity that can be achieved with hops and malt in lager beers.
At the far end of the yeast flavor scale lay the HefeWeizen yeast. These yeast were cultivated by Bavarian brewers for their extreme flavor contribution in wheat beers. The traditional HefeWeizen yeast produces fruity aromatic compounds called esters - principally the banana ester, isoamyl acetate. It also makes a host of phenolic compounds which are responsible for the clove, vanilla, cinnamon and smoky flavors. There are no fruits or spices added to a Bavarian-style HefeWeizen, despite what your tastebuds may be telling you. Together with the light tart flavor of wheat malt, these flavors combine to make one of the most complex yet refreshing and drinkable beers in the world.
Fermentation takes place over the course of about one week - lagers take more, ales take less time. When most of the sugar has been consumed by the yeast the beer is pumped back to our conditioning tanks.
