Is it a lager or an ale?

If you look up 'ale' in the dictionary, you'll read that it's a beer from the United Kingdom. Ale is top-fermented: during fermentation, the yeast is active at the top of the tank. It is also said that in ale, a portion of the added barley is roasted. Such an English ale is therefore often a darker beer. Lager comes from German. It is derived from the verb 'lagern', which means that the beer (or other foodstuffs) is placed in barrels to mature. A lager is a bottom-fermented beer; this means that the yeast is active at the bottom of the tank during fermentation.

Temperature

The main difference between ales and lagers is thus the fermentation. 'Top-fermenting' yeasts need higher temperatures to do their work; between 18 and 24 degrees Celsius. And 'bottom-fermenting' yeasts work best between 7 and 14 degrees Celsius. A mnemonic: top-fermenting yeasts work at a higher temperature than bottom-fermenting yeasts. Of course, there are brewers who explore the limits of where their yeasts can be active. They brew ales with 'bottom-fermenting' yeasts and lagers with 'top-fermenting' yeasts. This all has to do with the flavor they want to impart to the beer. Yeast is not only an alcohol producer but also a flavor enhancer.

Taste

In addition to the fermentation temperature and the location in the tank where the yeast is active, both variants also provide a diverse taste. Generally, top-fermented beers have more flavor influence from the yeast than bottom-fermented beers. Lagers are therefore often more drinkable and crisp. Top-fermented beers often have spicy aromas and fruity flavors.

In English-speaking countries, it is now standard that a bottom-fermented beer is called a lager, and a top-fermented beer is called an ale. A second mnemonic: bottom-fermenting works low, so those are lagers. We encounter ales a lot on the shelves. Not least because of the India Pale Ales or Pale Ales that are widely consumed nowadays.

Beer Styles

Whether a beer is top-fermented or bottom-fermented can often be deduced from the beer style. Pilsner, Schwarzbier, and traditional Bock beers are bottom-fermented. Famous top-fermented beers are almost all beers we call craft beers, such as Belgian blonde, tripel, wheat beer, IPA, and also witbier.
Sometimes a brewer considers the type of fermentation so important that the method of fermentation can also be found on the label. Premium lager is an example of this, as is the range of Belgian beers proudly displaying 'high fermentation'. How a beer is fermented naturally matters little to the consumer; in the glass, it's all about the taste and balance of the beer.