Beer is an amazing beverage that has existed for over 7 000 years. But what is it that makes the difference in different kinds of beer?

This is a question of which the answer is much more complicated than what we are going to talk about in this article, but it will give you a hint of the mystery. What is well known about it all is that the process of fermentation is crucial for the taste and character. There are three usual ways of fermenting beer, the difference between them is what kind of yeast is used, yeast, top-fermenting yeast and bottom-fermenting yeasts.

Spontaneously fermented – as it all started

Spontaneously fermented beer is the oldest kind of fermentation. The fermentation gets its start and power from the microorganisms that is in the air. This gives a more varied beer than other kinds of fermentations since it is not easy to control. When making a spontaneously fermented beer you start by brewing the original wort and pour it in to open, shallow vats. These are often situated in the top floors of the brewery. These vats are often no higher than 30-40 cm to make as large an area as possible for the original wort to contact the air. After this it is tapped to barrels in sizes varying from 250 to 10 000 litres, usually old wine barrels. To make sure the process isn´t too fast you only make this kind of spontaneously brewed beers during the colder season of the year. The process contains of different steps, the first months is when the beer gets its percentage of alcohol, then lactobacterias take over and gives the beer its acid. After a year the bacteria called brettanomyces that is dominating the beer. This process concludes in beers that are most usual in Belgium and called Lambic. Other variants of spontaneously fermented beers are Gueuze and Kriek.

Bottom fermenting yeasts

When making beer with bottom fermenting yeasts you let the beer ferment slowly at a low temperature (6–12 degrees Celsius) which makes the yeast fall to the bottom. More than 90% of all beers are made like this and is also called light beer. The technique is relatively young, made in the 19th century. This process makes a light fresh beer with an extensive range of sustainability. The bottom fermented beer has a distinct and pure character of malt and hops as opposed to the top fermented beers. Most bottom fermented beers are called lagers which comes from being fermented over time.

Top fermented beers – more taste and scents

Top fermented beers are fermented in temperatures between 14 and 20 degrees Celsius. Because of the high temperature the yeast will rise with the carbon dioxide to the surface why it got the name top fermented. Characteristic for this kind of beers is that it gives a fruity flavour and they often smell more than they taste. Most top fermented beers go by the name ale but also wheat beers count as a top fermented beer.  In Britain the beer market is dominated by Ale but bitter, porter and stout are common top fermented beers. The yeast used in the process comes from spontaneously fermented beers. Louis Pasteurs discovery about one cell microorganisms’ part in the process was crucial when it comes to turning sugar into alcohol.