Brewing SolutionsBeer Fermentation: Find Answers to All Your Queries on the Fermentation Process in Beer Brewing

Hello aspiring brewers! Welcome to another exciting post as part of our beer school series. In this post, we discuss one of the most crucial steps in beer brewing – the fermenting. If you have wondered what exactly happens during the fermentation process, how to ensure that you’re in control of the fermentation process and not the other way round, it’s time to buckle up for a foamy ride, as we explore the secrets of fermenting your beer.

First let’s get the definition right,

What is beer fermentation?

Technically, fermentation is the process of converting the fermentable sugars into carbon dioxide and ethanol equally, with the help of yeast aka the fermenter. In beer brewing equipment, fermentation happens in either one of the following two ways:

  • Top fermentation – Used in the manufacture of ales
  • Bottom fermentation – Use in the manufacture of lagers

In simpler terms, fermentation is the process that adds the fizziness to your beers naturally.

Steps in the beer fermentation process

To kick-start fermentation, yeast is added to the fermentation vessel – this is a large urn that is part of the beer making machine. The yeast converts the wort solution from the previous stages into beer with alcoholic content and carbon dioxide bubbles. Once the fermentation is finished, the liquid leftover is known as the “Green Beer.”

The wort is the sugary solution that is formed by mashing malt and boiling the hops. Wart becomes beer after the fermentation process.

How long does fermentation happen during beer making?

The exact duration depends on the type of beer, size of the batch and other factors like strain of yeast, temperature and more. Generally, it takes around two weeks from start to finish for the fermentation to complete.

Can over-fermentation happen?

Well, it’s a tricky question. Generally, over-fermentation is not possible as the yeast can consume only certain types of sugars in the wort. When all these sugars are depleted, the fermentation comes to a stand-still. The yeast settles at the bottom of the liquid, doing nothing.

But you don’t want this to happen. As the yeast settled at the bottom gives a funky flavour to the beer which doesn’t taste good.

Will the flavours vary depending on the type of yeast?

Yes! Just like different spices give different results to your curry, different strains of yeast lead to differing end results. For example, some yeasts will give a crisp, clean flavour, while other strains of yeast give a bready flavour. The strain of yeast you use depends on the flavour profile you’re hoping to achieve.

Is Beer a Fermented Drink?

Yes, due to the fermentation process, beer is classified as a fermented drink like Kombucha. When consumed in moderation it gives the health benefits of other fermented foods like lowering the risk of cancer, diabetes and stroke.

What is the role of temperature in the fermentation process?

If the temperatures become too high, then it could kill/knock off the yeast, preventing complete fermentation. This is why, we recommend including cooling tanks as part of your beer brewing equipment to keep the temperature under control.

Check out the preferred temperature and duration for different types of beers:


Beer StyleFermentation TemperatureFermentation Duration
Ales20 – 22° CFor two weeks
Lager7 – 13° CAround six weeks


What’s the Difference between Primary and Secondary Fermentation?

Primary Fermentation –

In this stage, the yeast does the fermentation process.

Secondary Fermentation –

This happens when the brewer takes the beer from the primary vessel and moves to another container for storage.

Are Primary and Secondary fermentation the same as Top Fermentation and Bottom Fermentation?

  • Top-fermented beers contain yeast that floats at the top of the tank. These beers prefer warmer temperatures during the fermentation process and includes beer styles like pale ales, porters, stouts, brown ales.
  • Bottom-fermented beers contain yeast that floats at the bottom of the tank. These beers ferment at low temperatures. Some of the popular styles of beers include Pilsners, Oktoberfest lagers and Vienna lagers.

That’s it, we’ve come to the end of this post and we hope this clears all your queries about beer fermentation. For any further queries, drop us an email and our expert brewers and beer equipment consultants will get back to you.