Brewday 15/02/2019 - Lager and Kolsch

One Brew - Two Beers

I've been wanting to brew a lager for ages but it's difficult without temperature controlled fermentation - lager yeasts generally ferment at 10-12°C, compared to ale yeasts which are quite happy at room temperature. However, I thought if I could utilise the twin benefits of cold weather and a draughty Edwardian house I may have a chance of success. After a bit of checking with a thermometer I discovered that the cupboard under the stairs (unheated, north facing, non cavity external wall and a bit draughty) was only around 12°C and the ambient temperature of my mains water was just over 8°C. This meant I could easily chill the wort down to 14°C with my immersion chiller and keep the temperature low during fermentation. I planned to use Saflager W-34/70 lager yeast which has a recommended required fermentation temperature of 12-15°C. Originally I only intended to brew a small batch (12lt) which I would ferment in three demijohns. However I also had one pack of Kolsch yeast and plenty of suitable malt and hops so decided to brew around 30lt of beer, 12lt fermented with the lager yeast and 18lt with the kolsch.

Recipe (BIAB) + sparge

Since this recipe would result in a boil size of approximately 35lt (which almost fills my pan) I took a slightly different approach to this brew. Firstly I heated my initial mash water in two pans, 20lt in my usual brew kettle plus an extra 10lt in another stock pot. Secondly, as I was using almost 6kg of grain I reverted to my original large brew bag. This was basically to allow easier handling of the water for the mash and the grain bag pre-boil. Once the water had reached the strike temperature of 72°C I placed the large pan on the kitchen floor in its insulated jacket, put in the grain bag and added the additional 10lt of water from the second stock pot. Then I carefully added the grain, stirring well to avoid any doughballs. Once the mash was complete I lifted up the grain bag, let it drain into a fermenting bucket and sparged the grain bed with 8.5lt of 76°C water. While this was happening the pan was heating on the hob. Once all the water had drained through the grain bed and rinsed out all the sugars I transferred the contents of the fermenting bucket into the pan which gave me a pre-boil volume of about 35lt.

• Mash water (72°C) 30lt 
• Sparge water (76°C) 8.5lt
• Vienna Malt 3kg
• Lager Malt 2kg
• Munich Malt 0.5kg
• Wheat Malt 190g
• Carapils 250g
• Perle 4.4% 50g 60mins
• Pacifica 5.36% 15g 30 mins
• Pacifica 5.36% 10g 15 mins
• Crossmyloof Kolsch yeast 1 pack
• Saflager W-34/70 1 pack

Once the boil had finished I was left with 29lt of wort. After chilling to 14°C I transferred 12lt into three demijohns and pitched the lager yeast, the remaining 17lt went into a normal 25lt fermenter with the kolsch yeast and an extra 2lt of water to bring the original gravity down as better than expected efficiency (86%!) meant I was going to get two beers with abv's in excess of 6%.

Results:

Kolsch!

Firstly the Kolsch which I fermented in my kitchen for 10 days at around 16°C. I pitched at 14°C but the temperature soon rose to 16-17°C so I used a wet towel to keep it cool.

• OG: 1.049
• FG: 1.008
• ABV: 5.3%
• IBU: 26

Very clean and crisp. A little bit floral with just a hint of apple flavour. A bit more malty compared to my previous efforts, maybe due to the Vienna and Munich malts, more like a lager really but very nice.

Next the lager which was fermented for 10 days at ­12-14°C and then another four days at room temperature finishing at 18°C. 

Lager!

• OG: 1.055
• FG: 1.008
• ABV: 6.1%
• IBU: 27

This was my first attempt at a proper lager and I am very pleased with the end result. It's clean, crisp and crystal clear (despite no finings as usual). Compared to the Kolsch there are no floral or fruity flavours, the lager yeast is very neutral which lets the malt and hops provide all the flavour. I fully intend to make a lager again, perhaps a dunkel or doppelbock next time.