I was having a conversation with a friend about Belgian beers…

One of the things I pointed out was that Belgian brewers typically bottle their beers… few of them keg their beers to serve on tap…

Depending on the beer style (and the brewery), some go through a secondary fermentation in the bottle and others don’t…

… but this brought about a whole other topic of ‘what exactly does it mean to double ferment your beer?’

Well, let’s start at the top…

The way I think of fermentation is yeast eat sugar…

If yeast are eating sugar then there is fermentation going on… if they are not eating sugar then no fermentation is happening…

In the case of Belgian beers, double fermentation is referring to yeast eating sugar in the bottle… basically priming the beer and bottle conditioning…

… but there is a slight difference in the case of Belgian brewers… they don’t just add priming sugar, they also add fresh yeast when bottling…

So as usual, I read up on the topic and started to ask ‘why?’…

Why bother adding fresh yeast to the beer at bottling?

The only time I had heard of adding fresh yeast at time of bottling is if you accidentally froze a lager and are worried about yeast viability during bottling conditioning…

But in this case it has more to do with the levels of carbonation of the beer…

Belgian beers can be highly carbonated… the fresh yeast is to make sure that all the simple sugar is turned into CO2 and avoid an overly sweet tasting beer…

But priming your beer and bottle conditioning is only one way to double ferment your beer…

There is another way to double ferment your beer…

Krausening…

Krausening is a bit more advanced than just priming beer… krausening takes an actively fermenting beer and it is added to a beer that is almost done fermenting…

You can see how I did this by watching my video on How To Brew A Schwarzbier…

The idea behind Krausening is that as yeast are almost done fermenting, they begin to clean up esters and other by-products that may produce off flavors…

However, in a typical lager, these by-products may not be cleaned up all the way… when you add an actively fermenting beer to a beer that is almost done fermenting, you are essentially adding fresh ‘active’ yeast which will help clean up the beer better…

Krausening started as a way to carbonate beers… you can simply add an actively fermenting beer to your beer that is almost done fermenting and bottle your beer… this will carbonate your beers a bit faster and change the character of your beer…

… but you don’t have to stick to using Krausening just to carbonate your beers… when you understand Krausening you can find other advanced uses, which I cover in my training program Mash Control…

You can also watch the Schwarzbier Home Brew Review to learn more about the results of Krausening your beers…

Cheers!


    1 Response to "Double Fermenting Your Beers"

    • arturo

      to say belgians dont keg beer is not correct. they seem not to export kegs, but locally you can find many taps.

      2nd fermentation in Belgian beer does take place in a Secondary fermentation container, the secondary fermentation cleans the beer. the 1st fermentation is as you said, yeast eating the sugar— but leaving residues.. the second fermentation, the yeast goes back and eats all those residues (their 2nd choice). Some might add additional yeast because Belgian beer is brewed is brewed to high alcohol and that yeast starts to having a tough time to survive, so you add a little more to keep them going.

Leave a Reply

Your email address will not be published.