Marzen Style Ale

By: anthony On March 18, 2022

I am a sucker for lagers. As my palate has changed over time, I've moved far away from hoppy IPAs and Pale Ales and more towards malt-forward lagers. However much I love the style of beer, the one factor in keeping me from brewing them is the fact I do not have a fermentation chamber to cold-ferment a lager.

Enter Oslo, a Norweigan Kveik strain. Oslo is one of the most neutral strains of yeast I've ever encountered. It can be fermented up to 100ºF without throwing off fusel alcohols or any kind of esters. It is, essentially, the most boring yeast ever. I've brewed a couple of Table Beers with it and wanted to see if I could faithfully recreate a lager. As boring as Oslo is, that is also what makes it great - an ale yeast that ferments clean at all temperatures in its range. That meant I should be able to use it in a lager-style ale.

It just so happened that a friend wanted to start learning how to brew and she really wanted to make a Marzen. It gave me the perfect excuse to test out Oslo in a lager-style ale setting. So, I put together a simple Marzen recipe that Oslo would work well with.

The recipe utilized entirely German malted grains and German hops. The goal was to keep this as traditional as possible with the exception of fermentation.

Bill PercentageFermentable
48.7%Weyermann Vienna
48.7%Weyermann Dark Munich
2.7%Weyermann CaraMunich I

I decided to use a single-infusion mash for this beer, mashing in at 152F for 60 minutes. During the mash, this beer was treated with 4g of Gypsum and 4g of Baking Soda to match my water to the Munich (Dark Lager) profile in Brewer's Friend. After mashing, I recirculated the beer until it ran clear and added the first wort hop charge.

Once I collected my total volume, I began the boil and boiled for 60 minutes, adding the last hop charge at the appropriate time. After boiling I quickly chilled to about 80F, using an immersion chiller, and then transferred into a carboy where I pitched a few flakes of dried Oslo.

I fermented the beer at 90ºF and left for a couple of days. When I returned home four days later, it had finished fermentation. I proceeded to keg it into a freshly cleaned and purged keg and carbonated it to 2.6 vols.