Firstly I decided I didn’t want to use a lacto culture because I didn’t want to introduce lacto to my equipment and I wanted to have a Berliner ready as quick as possible. Using lacto to ferment would mean a longer fermentation to get a really nice sour. This meant I needed to sour my mash or wort, then use a boil (traditional Berliner weisses are not boiled) to kill off the lacto before pitching into my fermenter.
After thinking it through I decided to sour my wort because I felt this easiest and I thought I has the best equipment to pull it off.
Since this was my first time I only used a ~3 gallon batch.
2# pilsner malt
2# wheat malt
2# wheat malt
0.5 oz hallertau 15 minutes.
Mashed at 154F for 60 minutes.
Once I drained my mash tun I put it into a bucket that I bought specifically for this lacto purpose. After it cooled to 110F, I threw in a handful of grain (grain naturally carries lacto on it) and then put an airlock and lid on the bucket and put it in my fridge that I normally use for fermenting. I had put a light bulb in which I turned on and used as a heating source and it was kept insulated by the fridge, essentially creating an incubator. I maintained the fridge as close to 110F as possible because that is around the highest temperature that lacto likes to do its work without being killed (which occurs around 120F). As the wort began souring it gave off a creamed corn smell and when I took a sample it had a nice puckering sour. I was going for a big punch-you-in-the-mouth flavor so I soured it for 4 days.
After day 4 I boiled and hopped for 15 minutes for a low IBU and pitched a starter of a kolsch yeast. I ended up adding raspberries for about a week after primary fermentation then bottled it and will be trying one tomorrow.