Differences between Ale and Lager
Contents
Comparison Article[edit]
The primary distinction between ale and lager is the species of yeast used during the fermentation process and the temperature at which that process occurs. All beers fall into one of these two broad categories based on these technical production methods. While modern brewing has created styles that blur these lines, such as Kölsch or steam beer, the fundamental classification remains biological.
Comparison of Ale and Lager[edit]
| Feature | Ale | Lager | ||
|---|---|---|---|---|
| Yeast Species | Saccharomyces cerevisiae | Saccharomyces pastorianus | ||
| Fermentation Temperature | 15–24 °C (60–75 °F) | 7–13 °C (45–55 °F) | ||
| Fermentation Position | Top of the vessel | Bottom of the vessel | ||
| Aging Process | Short (weeks) | Long (months) | esters (fruity) | Low esters (cleaner) |
| History | Ancient (thousands of years) | Post-15th century (Bavarian origin) |
Yeast and Fermentation[edit]
Ales are brewed using "top-fermenting" yeast, *Saccharomyces cerevisiae*. During the fermentation process, the yeast cells rise to the surface of the liquid, forming a thick layer of foam. This species thrives at room temperatures, usually between 15 and 24 °C. The higher heat causes the yeast to produce more esters and phenols, which contribute aromatic notes often described as fruity or spicy.
Lagers utilize *Saccharomyces pastorianus*, a hybrid yeast that is "bottom-fermenting." These cells settle at the bottom of the fermentation tank. This species is adapted to work at lower temperatures, typically between 7 and 13 °C. Because the yeast works more slowly and at lower temperatures, it produces fewer fermentation byproducts, resulting in a flavor profile that is primarily defined by the malt and hops rather than the yeast itself.
Conditioning and Storage[edit]
The word lager comes from the German verb *lagern*, meaning "to store." After the initial fermentation, lagers undergo a period of cold storage called "lagering." This stage lasts from several weeks to several months at temperatures near freezing. Cold storage allows the yeast and proteins to settle out of the liquid, which increases the clarity of the finished beer. It also allows the yeast to reabsorb certain chemicals, such as diacetyl, which can produce an unwanted buttery flavor.
Ales generally do not require long-term cold storage. Once the primary fermentation is complete, ales are often conditioned at higher temperatures and can be ready for consumption within one to three weeks. This shorter production cycle made ales the dominant form of beer in most cultures until the development of industrial refrigeration in the 19th century allowed for the year-round production of lagers.
Varieties[edit]
Common styles of ale include India Pale Ale (IPA), stout, porter, and wheat beer. These styles often emphasize the complex chemical profiles generated during warm fermentation.
Common lager styles include pilsner, Märzen, bock, and Dunkel. These beers are characterized by a "clean" finish, a term used by brewers to indicate the absence of fruity yeast aromas.
References[edit]
- Fixsen, J. (2011). Principles of Brewing Science: A Study of Serious Brewing Issues. Brewers Publications. ISBN 9780937381946.
- Bamforth, C. (2003). Beer: Quality, Safety and Nutritional Aspects. Royal Society of Chemistry. ISBN 9780854045884.
- Hornsey, I. S. (2003). A History of Beer and Brewing. Royal Society of Chemistry. ISBN 9780854046300.
