A Kölsch is described by the latest BJCP and Brewer’s Association style guidelines as “straw to golden in colour, with a delicate balance of malt, ester, and hop character, moderate bitterness, with a well-attenuated, soft finish”. The recipe for one is simple enough as well: Pilsner malt, German noble hops, soft water and German ale yeast. Yet while it all sounds easy to visualise, it is hard to achieve. The primary difficulty is achieving the delicate balance between the malt, hop and fermentation characters. The malt and hop balance is relatively easy, it’s taking that balance and balancing it with the subtle apple and pear esters that is the trick.
Fermentation and maturation
The big secret to brewing Kölsch is a cold fermentation with German ale yeast. This is the traditional brewing method – essentially the relatively newer (1800’s) lager brewing mentality using the older German ale strains (1600s). The goal of this fermentation is to produce a brilliantly clear beer, with a low, soft ester character. It would be easy to use these same ingredients to brew a bigger meltier beer, or a hoppier beer, or a more estery beer.
But the essence of drinkability is balance, and that is what is achieved here. That being said, there is still a lot of latitude displayed in the actual examples of this style. Many of the Kölsches of Cologne have a more pronounced hop character, while some are more malty or more estery – the trick, as I said earlier, is not to lose the balance between these aspects.
There are several Kölsch yeast strains on the market, some labelled Kölsch and some labelled simply as German Ale. The key aspect of this yeast strain is the signature apple and pear esters it provides, not to be confused with the green apple, cidery, and/or sliced pumpkin character of acetaldehyde.
This is an otherwise normal ale yeast that is pitched cold and fermented cool to minimise the ester profile, while still providing for a fully attenuated, dry and crisp beer. While the exact temperatures can vary with the particular strain or cultivar you are using, generally you should pitch cold at 12-14.5°C and then ferment at the relatively cool temperature of 15-16°C. Because this is a low temperature for ale yeast, a higher pitching rate is warranted, typically 1-1.5 billion cells per litre per degree Plato.
The typical gravity range of this style is 1.042-1.050, or 11-12°P, give or take. This equates to 220-360 billion cells for 20 litres or roughly 2-3 yeast packages. Both under-pitching and overpitching beyond the noted range (1-1.5) will likely induce higher sulfur dioxide (struck match) levels in the beer, which conflict with desired drinkability and balanced hop character.
The same caution applies to wort aeration, typically looking for 1 ppm per degree Plato, in this case about 12 ppm, although this factor is also dependent of specific yeast strain and form. A dry yeast product will not need as much oxygen as a liquid yeast product.
Once the yeast has been pitched, the wort temperature should be allowed to rise from (for example) 14°C to 16°C during the next 24-48 hours, and then held at 16°C for at least one week. Many Kölsch brewers do not utilise a diacetyl rest, relying on the higher pitching rate and constant temperature and an additional week to achieve maturation before cooling.
Other brewers will raise the temperature to 18°C (for example) and conduct a diacetyl rest for 2-4 days before cooling. Both methods work, but I would encourage you to use the warmer diacetyl rest if the fermentation seemed sluggish.
After fermentation and maturation are complete, it is time to cool the beer for cold conditioning. Do not Cold Crash your beers! I don’t know where this practice originated, but it kills your head retention due to lipid release from the stressed yeast! Cool them gently – cool them at 3°C every 12 hours until you get to near 0°C, then hold it there for 2-4 weeks for the haze and yeast to drop. Fining with gelatin or other clarification aids will help.
Ingredients
Now that we have covered the important part, we can talk about ingredients. This style falls between a German Pilsner and a German Helles, not as bitter typically as the Pilsner, but not as malty sweet as the Helles. A typical recipe would be 90% Pilsner malt with 10% Vienna or Wheat malt, depending on if you were looking for a sweet versus grainy malt character. I prefer the Vienna option, myself. The final part of the grist is Acidulated malt to help lower the mash and beer pH to the 5.2-5.6 range, which should produce a brighter tasting beer.
The hop character should be German, generally something like Hallertau Mittlefrüh or Tettnanger, or the like. Not Saaz (if you are trying to stay true to style), because that’s Czech. On the other hand, some of the newer German varieties like Hüll Melon, Tradition, or Mandarina Bavaria would complement the ester profile nicely. You are generally looking for a 60 minute bitterness addition of 20-25 IBUs, ie. roughly half the OG to achieve good balance. Next you will want a small addition (3-5 IBUs) late in the boil (15 minutes or less) to add a touch of hop aroma and flavour. Some real world examples of this style are noticeably hoppy. However, I would not use whirlpool or dry hop additions.
The water profile for this style should be soft yet crisp, which means a lower level of minerals overall, but with a balanced to slightly more sulfate sulfateto-chloride ratio (ie. 1-1.5:1). For example, using four grams of calcium sulfate and three grams of calcium chloride in 25 litres of RO or distilled water would yield a profile of: 70 Calcium, 0 Magnesium, 0 Alkalinity, 90 Sulfate, 60 Chloride, 0 Sodium, and -50 Residual Alkalinity. This is a relatively soft yet crisp profile.
John Palmer’s Essential Kölsch Recipe
All grain (expected figures)
OG: 1.045
FG: 1.010
ABV: 4.7%
IBU: 25
EBC: 6
Volume: 20L
Ingredients
3.5kg Pilsner Malt
450g Vienna Malt
110g Acidulated Malt
30g Hallertau Tradition (6%)
20g Hallertau Mittelfrüh (4%)
3 packages of Kölsch, German
Ale, or California Lager yeast.
Method
1. Mash in at 65°C for 60 minutes.
2. Sparge and transfer to kettle.
3. Bring to the boil.
4. Add 30g Hallertau Tradition hops for a 60 minute boil.
5. With 15 minutes left on the boil add 20g Hallertau Mittlefrüh hops.
6. Cool wort to 14°C and run into fermenter.
7. Oxygenate or aerate well and pitch yeast.
8. Ferment at 16°C for about 10 days, then increase to 18°C for two more days.
9. Slowly decrease temperature 3°C every 12 hours to cold condition for two to four weeks.
10. Keg or bottle as usual.
Extract with specialty grain (expected figures)
OG: 1.045
FG: 1.010
ABV: 4.7%
IBU: 25
EBC: 6
Volume: 20L
Ingredients
2.6kg Pilsner extract
450g Vienna Malt
110g Acidulated Malt
30g Hallertau Tradition (6%)
20g Hallertau Mittelfrüh (4%)
3 packages of Kölsch, German Ale, or
3 packages of Kölsch, German Ale, or
California Lager yeast.
Method
1. Heat six litres of water in your brew pot to 70°C.
2. Add cracked specialty malts in grain bag and mash at 65°C for 40 minutes.
3. Remove bag from wort and allow to drain, increase the heat.
4. As the water heats up, add half the pils extract and stir to dissolve.
5. Once boiling, add 30g Hallertau Tradition for a 60 minute boil.
6. With 15 minutes left on the boil, add 20g Hallertau Mittelfrüh.
7. Flame out then cool wort and transfer to fermenter.
8. Add remaining extract and stir to mix while adding water.
9. Top up with cool water to the 17 litre mark and stir vigorously.
10. Check the temperature and top up to 20 litre with warm or cold water (refrigerated if necessary) to hit 14°C.
11. Aerate well and pitch the yeast.
12. Ferment at 16°C for about 10 days, then increase to 18°C for two more days.
13. Slowly decrease temperature 3°C every 12 hours to cold condition for two to four weeks.
14. Keg or bottle as usual.
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