Recipe Type: All Grain
Yeast Starter: no
Additional Yeast or Yeast Starter: BKYeast brett blend
Batch Size (Gallons): 12
Original Gravity: 1.028
Final Gravity: 1.000
IBU: very few
Boiling Time (Minutes): none
Primary Fermentation (# of Days & Temp): 3-5
Secondary Fermentation (# of Days & Temp): 0-2 months
Tasting Notes: Light bodied and refreshing tart wheat beer
There are a number of Berliner Weisse recipes in this section and several are similar to mine, but I have had enough people ask that I'll add this one to the fray.
I usually shoot for 1.028ish, which with losing some sugars during the sour mash, probably results in a beer around 3-3.2 abv. I really have no idea how adding fruit might change the abv. I don't see why this technique wouldn't work for a higher grav beer, but a smaller one might be pretty thin.
Recipe is very simple, 50% pilsner malt and 50% wheat. I use Riverbend 6-row pils and turkey wheat, but if you don't happen to live near a micro-malthouse, Weyermann would be my second choice. Getting 70% efficiency I use 6.5 lbs of each for a 12 gallon batch. I get a ton of trub and shoot for 5.5gal in ea of 2 fermenters.
I do a step mash in a cooler starting at 133F for 45 minutes, 1qt/lb. Add enough boiling water to get you up to 152 for 15 min. I'm sure that's a fixed amount, but I usually just add and stir til the temp is right. Pull 3qt-gallon-ish (depending on thickness, again relax) decoction, add 1/2 oz of whatever low alpha preferably german and noble not that it matters hops you have laying around and boil for 20 minutes. Return to the mash and you should be at mashout temp 165-170. Add sterile water to get mash down to 120ish and then add a few ounces or up to a half pound of crushed malt. If you have a 5 gallon round cooler, it should be perfect. If not, as long as you cover the surface of mash with plastic wrap, headspace in the cooler shouldn't be a problem. Flushing with CO2 is a very good idea. Without creating an anaerobic environment, you just have to hope that the lacto makes out competes everything else. The mash schedule is one of several in Brewing with Wheat.
If you've got room, you can add boiling water as needed to get the temp back up, but if you have a full cooler with no headspace, it will hold pretty well, especially if you can help it out externally. You can set up a heat lamp in a fridge with temp control, stick it in a tub with an aquariuam heat, space heater, blankets, whatever. 110 is probably ideal, I've had the sour mash get as low as 90 and it's been fine.
I'm usually happy with the sourness after 96 hrs or so. I've heard of sour mashes going much faster, but mine are usually right at 4 days before I'm happy with the tartness. If you've got a pH meter, you're ahead of me. I have used wine pH strips, but I don't think my tongue is any less accurate than those. Batch sparge as normal other than being no boil. When you hit target volume, 11 gallons for me, you're done. Heat the wort to 170. I use an immersion chiller so I just heat that up with the wort.
I ferment with a half pack of 05 per carboy and about 50mL of brett slurry. You might have a hard time getting the brett I use as it's from a home yeast rancher so feel free to experiment. The strains I use are all isolated from Cantillon and I think it works very well with the fruit additions. The interplay with the fruit is secondary, I find that the brett does a good job of cleaning up the off flavors than can be associated with sour mashing. Wyeast Lambicus would probably be my easy to get choice or maybe both that and brux. Using something like a Kolsch yeast instead of 05 would probably be better, but it's not something I keep around and 05 is easy.
Beer will probably ferment out in 3-5 days and in a week at most be ready to package or rack onto fruit. I can generally get 9 to 10 lbs of fruit and 4.5 -5 gallons of beer in a 6 gallon better bottle. That is very full and berries will tend to need a blow off and possibly try and clog the tube for good measure. That usually leaves 1-2 gallons of plain to drink while waiting on the 2 fruit beers. 2 lbs/gal is my starting point. You can leave on fruit for as little as two weeks if you plan on kegging and want more fresh fruit flavor. I bottle and like a more integrated taste which I feel takes about 2 months on the fruit.