Kölsch yeast experiment

So one of my favourite beer styles is Kölsch. While I’ve never been to Cologne where the style originates, I’ve had a couple of them and brewed them to the best of my ability, doing reasonably well in competitions with them. The trick is to mash for dryness, either a step mash or a 62-63C single infusion, with a long mash of 75-90 mins, and get the yeast right.

This is where this experiment comes in. I’m trying to find the best yeast choice for both my homebrewed efforts and for when I eventually make the leap to going commercial, and there’s a multitude of options out there now.

The yeasts of choice for this experiment are the new Lalbrew Köln dry yeast, Gigayeast’s GY021 and White Labs WLP029. Before I’d started this I have also used Wyeast 2565, rumoured to be the Weihenstephan 177 strain, and the White Labs European Ale strain, as well as WLP036 Alt. 2565 and European Ale are good flavour wise but take forever to clear to brightness, and WLP036 isn’t a kölsch yeast, it makes alright beer but I left it out.

Yeasts… The WLP029 was probably 15mL of thick slurry. Gigayeast was split up into 4x vials so approximately 50+ billion cells pitched.

Recipe was simple – 94% Pils , 4.5% Wheat, 1.5% Acidulated. Mash and sparge water adjusted with Phosphoric acid to hit a theoretical 5.2pH in Bru’n water along with about 4g of CaCl2 and 1g CaSO4 in the 15L batch. OG 1044, and around 27 IBU’s with Perle for bittering and Perle + Huell Melon for flameout. Looking back over my notes the Pils was actually a 60/40 split of 60% Barrett Burston Pale and 40% Weyermann Bohemian Pilsner.

Mash temperature

3x 5L demijohns were used for the fermentation, splitting the cooled wort into these, aerating each for around 1-2 mins with an airstone + bubbler then pitching. WLP029 was fresh slurry from a starter, GY021 was split from a fresh pack, and Koln was approx 5g rehydrated from a pack.

The demijohns.

Fermentation temperature was around 17C for all 3, and fermentation continued for 2 weeks – around 4-6 days active ferment and then conditioning / maturation at the same temperature – no cold crashing. Each demijohn got a small amount of Gelatin, and 2mL of White Labs Clarity Ferm was added during maturation to each, for no real reason other than testing that out.

Lag Time

WLP029 fired up first. GY021 was second and Koln took longer than both to get started and show signs of fermentation.

The WLP029 on the left is fermenting, but nothing’s happening over in the Koln!

Krausen

WLP029 had a decent krausen, GY021’s krausen was highest and Koln did eventually get a decent krausen, probably in the middle.

Sulfur & Diacetyl during fermentation

With only a small amount of wort no real sulfur was noticed near my fermentation, but pulling a couple of samples with a pipette did show a little more in the GY021 compared to the others. None of it stuck around though by the time it came to bottling.

I didn’t have enough of a sample to detect much diacetyl or run a forced diacetyl test during ferment but nothing seemed to be overly buttery after active ferment.

Attenuation & pH

The Koln took a fair amount longer in active fermentation than the other two. WLP029 was mostly over in 3-4 days, GY021 a little longer and then Koln probably bubbled away for 6 days. All of them seemed to still generate CO2 for a couple of days afterwards very slowly.

The final beers ended up a little different in attenuation, Koln 1.007, WLP029 1.008 and GY021 1.006. pH was around 4.1 for the Gigayeast, 4.2 for both the WLP029 and Koln.

Final Results & Conclusion

All 3 produced great, crisp and bright beer that’s the hallmark of a kolsch.

I’d have no hesitation in using any of these yeasts again, especially the Gigayeast 021 which may have now become my new favourite kolsch yeast, but the dry version is also good to my palate.

EDIT: I’ve tasted all the beers further now they’re carbonated and the WLP029 is no slouch, it’s crisp and clean. GY021 has a little more roundness of flavour, but there’s maybe a little harshness in the finish, and the dry yeast has a little bit of extra fruitiness/esters on the palate maybe a little like an English or American ale yeast, it’s not an overpowering flavour but noticeable. With such a subtle style any flavour sticks out, so all of these still made good beer, but really it’s a matter of preference as to how much flavour you want or prefer.

Over the next little while I’ll try out the beer with some other people and see what they think, while I don’t have enough beer to go full Brulosophy style with 20 tasters, it’ll be interesting to see what happens. And i’ve also entered the Gigayeast and Dry versions into a local homebrewing competition, so we’ll see what happens there (Edit: see the final section below for how it went)

I’ll take a couple of pictures when I can to show you how bright it is…

A note on price though… here in Australia at least there’s little difference in price between a vial of White Labs or Gigayeast and the 2 packets of the dry Koln yeast required to obtain the correct pitch rate recommended by Lallemand. I can see that a few microbreweries may like to use the bricks of this yeast to make Kolsch, clean ales or pseudo-lagers.

Other Thoughts

After I started this experiment, I also found some new gene sequence evidence that WLP029 may actually be a lager yeast… stay tuned for that one. It’s the same data from the Hittinger lab that Suregork was able to identify the Muri Kveik as being identical to WLP351 – http://beer.suregork.com/?p=4094 . I guess that explains some of the clean-ness and its use for “pseudo lagers” or quickly brewed lager-tasting beer in a lot of breweries…

Also in the same set of sequencing it turns out that WLP800 most probably is and WLP838 may be actually ale/cerevisiae type yeasts – these could also be interesting targets for an upcoming experiment.

Followup

I did pretty well with the GY021 and Lalbrew Koln versions at the recent NSW State homebrewing competition. The Koln-fermented version scored 84 points and the GY021 scored 78 points ( a couple of points lost from sulfur as it was only 2 weeks in bottle before tasting), however at the mini-BOS round in the category the GY021 ended up taking 1st place in the Pale Ale category and the Koln, 2nd place in the category. I guess maybe the sulfur disappeared a little between the scoring round and the placing round.

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