High or low fermentation
The decisive moment of the preparation of beer is for sure the fermentazione. Some yeast is inoculated in the must, that reacting with the sugars, it becomes a liquid that contain alcohol and carbon dioxide, that complete the maturation becoming beer, finally.
By and large, it is possible to state that the low fermentation takes place when the temperature required for the reaction of the yeasts is around 10°C and the high one when the yeast has a higher temperature (around 20-23°C). This distinction, however, in not completely correct: or better it is not only a matter of temperature. The fermentation, in fact, is defined high when at the end of the process, the left yeast go up on the surface, passing the must. It is defined, instead, low when the yeast when the residual yeast remain on the bottom of the fermenter.
High fermentation Lager Ale, low fermentation Lager, it is a matter of yeast
High fermentation beer is commonly called Ale, (from the Latin alere, which means feed), the low fermentation one, instead, is called lager, the main difference is in the yeast. The main difference is in the yeast: for the ales is suggested the so called brew yeast (scientific name: saccharomyces cerevisiae), which realization can happen at a temperature enclosed between 12° and 24°C. The lager is produced with the yeast:saccharomyces uvarum, also called carlsbergensis that derive from the name of the brewery that for the first time selected this yeast: Carlsberg.
This yeast needs a lower temperature, generally from four to thirteen degree. The high fermentation can be completed in few days, usually, no more than seven. The low one, instead is lower, and can require more than two weeks.
In comparison of the lager, the ale beers generally have a stronger taste, keeping in mind that there are some exceptions. There aren’t, instead, significative differences depending on the alcoholic volume
The different types of ale
Among the most innovative countries, high fermentation beers are spread mainly in Great Britain and in Belgium, whereas in Germany people prefer low fermentation beers, apart from the weizen
Under the name of ale there are numerous quality of beer, pretty different between them. Often, the only thing that they have in common is the fermentation method. The most common in the clubs of London and neighborhoods is the bitter ale, characterized by an abundant hopping that make it bitter. Other varieties, well appreciated, are the brown ale, dark and bitter with the aftertaste of dry fruit and the pale ale, than, on the contrary has a pale colour and it is less bitter and fizzy. The welsh prefers, instead, the mild ale, light and with a sweet taste.