Brewing a true lager takes a little bit more work and specialized equipment than brewing an ale. The most important factors in brewing a good lager outside of recipe formulation are: yeast strain selection, pitch rate, and fermentation temperature.
Beers brewed and fermented under the traditional souring method will develop a complex character and will sour through a long-time process, in which the production of lactic or acetic acids are produced by bacteria during the second fermentation and achieved generally in oak barrels.
Brewing beers with high original gravities (above 1.065) requires some modifications to normal brewing procedures. Factors that will determine success or failure in high gravity brewing are pitch rates, nutrient addition and oxygenation.
The purpose of propagating yeast is to produce a greater amount of healthy biomass free of contaminations, which will be pitched to accomplish uniform and stable fermentations.
Fermentation is the heart of the brewing process. During fermentation, wort created from raw materials is converted to beer by yeast. Fermentation is usually divided into three stages: primary, secondary, and conditioning (or lagering).
