Summer Brews | Kölsch-style Ale

While travelling through Germany with Sophie last year, I spent a good portion of time with a stein in-hand. Time was short, though I was fortunate enough to sample some excellent examples of Munich Helles, Hefeweizen, Pils, and even Schwarzbier. A great tragedy I reflected on while training out of the country, was not having the opportunity to visit Köln; and in particular, not to sample Kölsch – this unique cold-fermented ale the region is famous for.

Köln - a city as full of history as its local beer
Köln - a city as full of history as its local beer

The history of Kölsch is somewhat odd (in fact, a book has even been written on the topic!). To shorten a long story, this extremely refreshing ale-pretending-to-be-a-lager was born out of a trend-bucking decision in the 1600s that beers in the region be brewed using only top-fermented ale strains. To this day, only beers brewed in Köln can bear the name Kölsch. 

The BJCP describes Kölsch as follows:

A clean, crisp, delicately-balanced beer usually with a very subtle fruit and hop character. Subdued maltiness throughout leads into a pleasantly well-attenuated and refreshing finish. Freshness makes a huge difference with this beer, as the delicate character can fade quickly with age. Brilliant clarity is characteristic.

Sound delicious? It is! In fact, this brew has been commonly referred to as the ultimate “lawnmower beer”. Seeing as the weather is starting to heat up here in NZ, and there are plenty of lawns to be mowed, I thought I’d diverge from the Belgian theme and knock out this thirst-quenching drop.

Tools for the job

The grain bill for a Kölsch is typically heavy on the Pilsner malt, sometimes with a touch of Vienna or light Munich added for flavour (though the traditionalists would keep this to 5% of the bill or under). Wheat malt is not typically used for the style, but this is somewhat up for some debate. Given I wanted a golden, crystal-clear, malt-forward beer, I opted for a grist with ~ 90% Pilsner malt, and ~ 10% Munich. German noble hop varieties are commonly used for Kölsch (e.g. Hallertau, Spalt, and Tettnang), though homebrewed examples often feature other noble varieties such as Saaz. I decided to use what I had lying around from my last few batches – Nelson Sauvin (bittering), Styrian Goldings (boil), and Czech Saaz (whirlpool). A single infusion mash around 65 °C is commonly quoted, giving a highly fermentable wort. Lastly, choose your yeast carefully. Having read good things about Fermentis K-97, especially with regards to head retention, I thought I’d give this strain a whirl at the lower end of its temperature range.

Czeeky Wee Kölsch

Recipe Specifics
Batch Size (L): 22
Total Grain (kg): 4.40
Anticipated OG: 1.042
Anticipated SRM: 3.9
Anticipated IBU: 26.0
Brewhouse Efficiency: 70%
Wort Boil Time:  90 minutes

90.9% 4. kg. Gladfield Pilsner Malt (2.1 SRM)
9.1% 0.40 kg. Gladfield Munich Malt

12.00 g. Nelson Sauvin (Pellet, 11.30% AA) @ 90 min.
14.00 g. Styrian Goldings (Pellet, 2.60% AA) @ 30 min.
30.00 g. Czech Saaz (Pellet, 3.00% AA) @ 0 min.

Fermentis Safale K-97 German Ale Yeast

Water Profile
Profile: Bru’n Water ‘Yellow Balanced’

Mash Schedule
Sacch Rest – 60 min @ 65°C

Brewed 13/11/18

The night before brew day, I measured out the grain and brewing salt additions. I’m yet to sort out an RO system (suggestions welcome!), so I dechlorinated tap water for my mash addition using part of a Campden tablet. Excitingly, I now have a HLT with a couple of heating rods and a timer attached. I set the mash water to heat 1 hour before I planned to wake, and bedded down for the night.

Note the temperature controller from my fridge is attached to my hot liquor tun here
Ready to mash in!

When I woke my mash water was pretty much bang on strike temp. I added my brewing salts, milled my grains, and mashed in.

Bang on
A little lower than planned

After 5 mins to let the mash settle, I took temperature and pH measurements. The temp was bang-on, and pH was a touch lower than planned but perfect for the crisp style I was after. The mash was left to rest for a total of 60 minutes, stirring every 15 mins.

From here I lautered through a mesh bag zip-tied over my vinyl hosing given poor clarity despite vorlauf during my last brew. I added my brewing salts to my 75.6 °C sparge water, added to the tun for 10 mins then sparged.

A little less volume than predicted - I think my boil rate must be higher than estimated
Higher than predicted...

My sparge pH once equilibrated was 6.2 – higher than Bru’n Water had predicted, making me wonder whether I’d have some issues with tannins in this batch.

The see me rollin'...

Questioning whether my last batch indeed has a hint of DMS, I opted for the traditional 90 min boil this time, given the high proportion of pilsner malt in this grain bill. I achieved a nice hot break this time. Hops were added at the times specified above, though I did make a slight error with the final addition, only adding once I’d cooled the wort to around 45 °C my immersion chiller. That said, the wort had a great Saaz aroma in the end, so I guessed it would work out fine.

1.042 after temperature correction - around 70% efficiency

Once slightly above my groundwater temp, I siphoned the wort into a sterilised brewing bucket, splashing from a height to ensure good aeration. I popped an airlock on, and threw the bucket in my fermentation chamber to cool down to 15 °C before pitching the K-97 around 4 hours later. I usually rehydrate my yeast in 250mL of cool boiled water at least 30 mins prior to pitch. The following morning there were signs of a steady fermentation, < 12 hours later. Fermentation went as follows:

13.11.18: OG 1.042, K-97 pitched at 15 – 15.4 °C,  chamber set to 15 °C, bubbling < 12 hours later
18.11.18: 1.020, ramped to 20 °C as > 50% of apparent attenuation (target FG 1.010, hence 20/(42 – 10) = 62.5%)
20.11.18: 1.014
25.11.18: 1.007
28.11.18: 1.007 –> crashed by 5 °C per 12 hours, CO2 balloon attached to prevent oxygen ingress
29.11.18: sitting at approx. 7 °C, hence fined with gelatin.
3.12.18: having left to crash a little longer than usual due to working nightshifts, kegged to CO2-purged keg via dip tube. Set to 12 PSI at 4.5 

Ready for Christmas

Tasting notes 16.12.18: Light golden colour with relatively coarse bubbles though a nice lingering lace. Malty nose with only a hint of Saaz. Slightly tart, honey-malt flavour. Some body to support the beer though refreshingly dry.

Overall, I’ll be brewing this again! I’d plan to increase the pitching rate next time to see if I can reduce the ester profile, as I detected a small amount of isoamyl acetate in early tastings. Regardless, a perfect Christmas beer for the NZ summer.


Update: After around 6 weeks to condition on the keg, this beer is looking stunningly clear (see below). The flavour has really expressed itself now as the Germanic, malty, refreshing ale that I’d intended.

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