Berliner weisse is one of my favourite styles of beer to drink on a hot day. It's super refreshing and the low ABV means that you can drink it all day! With a raging summer already in progress, I decided to bite the bullet and brew my first sour beer.
Making sour beers at home can be a bit daunting. Firstly, there's the time and commitment of leaving something to age and sour for 6-12 months. I didn't have time for that - I wanted this beer on tap before Christmas! There are also sanitation issues to think about. I don't own any glass or stainless steel fermenters, so I was facing the prospect of having to sacrifice one of my fermenters to the gods of funk... not something I'm ready to do just yet.
Using a kettle souring technique, I was able to go from grain to glass in under 2 weeks. The added bonus? All of the souring is done pre-boil so the sour bacteria is killed off well before the wort goes anywhere near a fermenter.
Target OG: 1.030 IBU: 4.7
- Wheat Malt (50%)
- Pilsner (50%)
- 40 min at 64°C
- 10 min at 73°C
- Mash out at 78°C
- 500g of Acidulated malt to drop pH to 4.4
- Pitch WLP677 (lactobacillus delbruekii)
- Sit at 45°C or until pH reaches 3.4
Boil: (15 min)
- 21g Saaz CZ (pellet, 3.75%) at 15 min to 4.7 IBU
- Chill to 19°C
- Pitch 1 vial of WLP029 (German ale/kolsch)
- Rack onto 2kg of frozen raspberries in secondary.
Late Saturday afternoon I fired up the Braumeister and mashed in. After mashing, I added the acidulated malt to the wort and left it to do it's thang for half an hour or so. At this point my pH was only 4.8, not quite acidic enough for the lacto to start souring, so I added a little lactic acid to get it down to 4.4. If you're adamant about following The Reinheitsgebot, I reckon you could achieve the same thing by adding some more acidulated malt instead.
With the wort suitably acidic, I chilled it to about 45°C (using an immersion chiller) and pitched the lacto. To help create the anaerobic environment that lacto loves, I covered the wort with a layer of cling film. If exposed to too much oxygen, lacto will create acetic acid and make your beer taste like vinegar. A little fooling around with glad wrap is a small price to pay.
The wort needs to sit at around 45°C for 8 hours or so. I've heard of people using eskies and heat pads to achieve this. Luckily I have a Braumeister and was able to set it to 45°C and leave it overnight.
In the morning, there was some activity on the surface of the wort - a clear sign that the lacto had been busy. I was a little disappointed when a pH reading was only down to 3.8. I decided to bump the temp up to 50°C and leave it a little longer. 4 hours later I was really happy to see it was down to 3.3 and ready for the boil.
The 15 minute boil and single hop addition was over before I knew it. I chilled the wort to 18°C, oxygenated, and pitched the yeast.
The low OG and healthy yeast meant that primary fermentation was over in 4 days. At this point, I racked onto 2kg of frozen raspberries in a secondary vessel.
After 2 days on the raspberries, I kegged it and left it to force carbonate for a few days.
I couldn't wait to pour the first glass of this beer and it didn't disappoint.
As I'd hoped, it pours a very vibrant raspberry red colour with a creamy pink head and displays the sort of cloudiness you'd expect from a wheat beer.
The raspberry really hits you in the nose immediately and behind that there's a subtle bready/grainy aroma. I don't pick up anything sour or funky on the nose. That's not the case when you taste it though. Up front you get a big sour hit that reminds me of plums that are just under-ripe. The raspberry is not as prominent as the aroma and colour might suggest - it sits behind the sourness along with a slight hint of the wheat malt. There's a suggestion of acidity that I think this beer could do without, which I suspect means my glad wrapping skills weren't quite up to scratch.
This beer is very light bodied and quite dry which makes it so very smashable on a hot day. I can say for sure this won't be the last time I kettle sour a Berliner weisse.