A good majority of people think that all lagers are golden, light, and highly carbonated, and that all ales are dark, malty, and flat. Nothing could be further than the truth. You can get golden straw-coloured, biscuity Blonde Ales and dark mahogany, malt-forward, German lagers like a Dopplebock.
The only real difference between lagers and ales is yeast. Yep, that's it. Just a different strain of yeast is used. But since, a different yeast strain is used, it will behave differently, so the brewer has to consider altering the temperature of fermentation, duration of brewing, etc to result in a clean, tasty brew. So let's jump into it!
Etymology
The word ale comes from the Old English word aleau which derives from the Proto-Germanic word aluth. Aluth is most definitely a PIE root of the Latin word alum meaning 'bitter'. Bitterness is definitely synonymous with the flavour of many styles of ales like Double IPA's and American IPA's.
The word lager comes from the German word lagern which means to 'store away'. The etymology of this word lagern which refers to storing something away, it denotes how lagers were made back in the older times. In the 1400s, giant wooden casks were filled with lager and stored in cold caves in the mountains over the Bavarian summer and left to ferment naturally with an indigenous yeast culture we now know as the 'lager yeast'.
Yeast Strains
Ale styles are typically fermented with the yeast strain known as saccharomyces cerevisiae. The Belgian ale yeast strain, Wyeast 1388 Belgian Strong Ale Yeast (used to brew a Belgian Strong Ale) produces a strong, peppery phenol alongside a balanced orange and lemon-like ester.
Lager styles are typically fermented with the yeast strain known as saccharomyces pastorianus. The Bavarian lager yeast strain, Wyeast 2206 Bavarian Lager Yeast (used to brew a German Bock or Dopplebock) is used to brew rich, full-bodied, malty lagers.
Top vs Bottom-Fermenting
Ale styles are typically fermented with a top-fermenting yeast strain, such as saccharomyces cerevisiae. Top-fermenting essentially means that the yeast is applied to the top of the wort and at a warmer temperature than lagers are fermented with.
Lager styles are typically fermented with a bottom-fermenting yeast strain, such as saccharomyces pastorianus. Bottom-fermenting therefore entails that the yeast works from the bottom of the wort and at a far colder temperature than ales are fermented with.
Fermenting Temperature
Ale styles are typically fermented in warmer temperatures than lagers, usually ranging from 17-24 C°.
Lager styles are typically fermented in colder temperatures than ales, usually ranging from 8-14 C°.
Brewing Duration
Ale styles are considerably quicker to brew than lagers, usually ranging from 3-5 weeks. This shorter brewing process works in conjunction with the warmer fermenting temperature to produce an ale packed chock-full of esters.
Lager styles take a significantly longer time to brew than ales, usually ranging from 6-8 weeks. The lengthy brewing process results in the lager displaying a light body, crisp taste, and a clean character.
Ester & Phenol Character
Ales styles usually express greater ester character than lagers, which correlates with the warmer brewing temperatures used to brew ales. The Bavarian yeast strain used to brew Hefeweizen delivers powerful banana notes (due to the high levels of isoamyl acetate) as well as a spicy clove phenol (due to the presence of 4-vinyl guiacol).
Lager styles for the most part lack the strong ester character of ales, supposedly due to the colder brewing temperatures under the cold lagering phase. Due to this factor, Bavarian lagers (which offer minimal fruity esters) such as German Pilsners, are often described as having a light, crisp texture; whereas a Bock will displays sweet, toasty, and nutty aromas and flavours.
Now you're one step ahead! Yeast is a really, really complex unicellular fungi and to be honest, you don't need to know the science of it all. So there's the basics of yeast and how brewers utilise it through manipulating brewing variables to result in a true and satisfying end product.
By Lucas Barker, a budding craft beer enthusiast of 2-3 years. 21/04/22
Comments