What's the Difference between Ale, Lager and Spontaneous Fermentation

High fermentation, low fermentation and spontaneous fermentation.

Let's find out what are the differences between top fermented beers, bottom fermented beers and spontaneously fermented beers.

Beer is a fermented drink and not a distillate. In fact, it is obtained from the fermentation of wort, prepared with water, malt (mainly barley) and hops. But it is not even a simple barley and hop soup. Beer is in fact an alcoholic and sparkling drink. To obtain this result it is necessary to ferment the wort.

What is beer fermentation?

Fermentation is a process that allows living organisms to derive energy from particular molecules. In the case of beer, these organisms are yeasts, while the particular molecules are the sugars present in the wort.

Once the yeasts have been added to the beer, they will begin to feed on the sugars present in the wort, to accumulate useful energy for the reproduction of cells. Practically sugar becomes the food of every single yeast cell, which will generate alcohol and carbon dioxide (CO2) as a by-product, responsible for the sparkling character of the drink.


What are yeasts and what are they used for?

Let's start with an important statement: yeast-free beers don't exist. Although the discovery of how these microorganisms work was made in 1864 by Louis Pasteur, the father of microbiology, this does not mean that yeasts did not exist before. Yeasts and bacteria have always been used to produce different foods such as bread, wine, yogurt and much more. So beer is only one of the many types of fermented. In the case of beer production, however, there are specific yeasts for beer. Depending on the brewer's yeast chosen, very different results can be obtained.

Types of beer fermentation:

The fermentation of craft beer is not all the same. There are in fact many types of yeast: the choice of one type of yeast for beer rather than another greatly influences the final beer that will be bottled. The choice of types of malt and hops also influences the final result, but yeast is precisely that ingredient that literally brings beer to life. There are many types of yeast, but we can divide them into three main categories:

- low fermentation yeasts
- top fermentation yeasts
- yeasts and wild bacteria

The high and low or spontaneous fermentation will therefore be obtained based on the yeast chosen which will determine the type of final beer. Thanks to yeasts we can also reproduce the main styles of craft beer existing in the world. So let's see the difference between the various types of fermentation.

Bottom fermentation beer - Lager

Bottom fermentation beers are brewed with yeasts of the Saccharomyces Carlsbergensis strain. This family of yeasts has the particularity of working at a low temperature, between 7 °C and 14 °C. For this reason it is called bottom fermentation yeast. This type of yeast has a very neutral and clean character, so it does not affect the final taste of the beer much.

Styles of lager beer:
Bottom fermentation types of beers produced with Saccharomyces Carlsbergensis yeasts predict the name of Lager.

Precisely because the yeast used is very clean, this type of beers will mainly be characterized by the aromas of malt and hops. Some people believe bottom-fermented beers are just clear ones, but this is incorrect.

Certainly the best known Lagers have a golden color, such as Pilsner, Märzen and Munich Helles. However, there are also more intense colors, such as the Bock, up to the black Schwarzbier.

Lager meaning:
The most famous bottom-fermented beers are the German ones. The term Lager was in fact coined in Germany. It derives from the German word lagern, which means “to store”. In fact, in the past in Germany, beers were stored precisely in warehouses, where temperatures were very low. This allowed the beer to be stored better and to obtain a much cleaner product. This extreme clarity was obtained with an almost involuntary process, but which we know well today and is known by the term lagerization. To learn more about this technique, read the article "How to Lagering the Beer".

High fermentation beer - Ale

Top fermented beers are brewed using yeast strains from the Saccharomyces cerevisiae family and are called Ale.
The characteristic of this yeast family is that it works at higher temperatures, between 18 °C and 26 °C. High temperatures result in faster fermentation. These types of yeasts have their own flavor profile, which affects the final taste of the beer. In fact, when yeasts work at high temperatures, in addition to alcohol and CO2, they also produce a series of by-products, such as esters. These esters give specific aromas that we can define as peppery, spicy, fruity and phenolic.

Top-fermented beer styles - Ale:
If for the Lagers everything is played on malt and hops, in the case of the Ale there is a lot of play on the aromatic profile produced by the yeast.

For example yeast strains for Weizen (wheat beers) produce a classic banana and clove profile typical of this style.
In the case of Belgian ales and Trappist and abbey beers, the fruity and spicy character is very marked. In the case of dark beers, such as Stouts, they can produce hints of dried fruit.

Others, on the other hand, tend to enhance the sweetness of the malt, as in the case of the Irish Red Ale, while other strains tend to highlight the bitterness of the hops, as in the case of the India Pale Ale. Let's say that the world of Ale is much larger and richer in styles than that of the Lagers and where there is the greatest experimentation.

Spontaneous fermentation beer - Sour Beer

We have therefore seen that there are two large yeast families: Saccharomyces Carlsbergensis and Saccharomyces cerevisiae. However, there is a third type of fermentation: spontaneously fermented beers. In this case, a specific yeast strain is not used, but the beer is exposed to wild yeasts and bacteria, naturally present on surfaces and in the air. To do this, the must is placed in large open tanks, leaving it in contact with the air and oxygen. In this way, a spontaneous fermentation process is activated in the beer, which leads to truly unexpected results.

Types of spontaneous fermentation beer:
With this natural bacterial combination, Sour Beers are produced. Among the various types of spontaneously fermented beer we find, for example, the Flanders Red Ale, where the intensely fruity flavors almost reminiscent of red wine dominate, or the Berliner Weisse, where the acidic notes take on the flavor of lemon and green apple, accompanied by the classic aromas of wheat malt.

The Sour Beers:
The most famous Sour Beers, however, are also the strongest ones: let's talk about Lambic and Gueuze. In these beers we find aromas and flavors that are generally referred to as earthy, hay and horse saddle. While they may seem horrifying, they are actually very popular.

Sour Beer definition:
The name Sour Beer doesn't need much explanation. It is a very popular beer category worldwide. The strong and pungent flavors are not suitable for all palates, but at least once in your life I recommend that you try one before judging.

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