The best info I have come across for BW is in this thread:
http://forum.northernbrewer.com/viewtopic.php?f=4&t=43587&hilit=berliner
The good information is not from the OP. A user named Mashweasel. I will sum up his experience (he is a pro from how it reads), but reading the whole thread is probably a good idea.
Mashweasel: Sour mash is a very bad idea. Ive done alright with mine and its 50% pils 50% wheat, single decoction with a mash hop. NO, boil. Thats right, NO boil. Ferment 4 days in primary, 3 day 2ndary, into the bottle with fresh yeast: bacteria.
Mashweasel:The souring of the beer comes from the lactobacillus found on the grain when it ferments, NOT before fermentation. As I said before. A simple grist of 50% wheat and 50% pils is the way to go. Something like 10 IBUs of any german hop will be fine of which they will be mash hopped. A single decoction is a must b/c this beer is not boiled. A sour mash will not accomplish the level of sourness, carbonation and dryness for which this style is known. Pitch both ale yeast and lactobacillus.
Fermentation: Open fermentation for 4 days, starting at 68F going up to 75F. 2ndary, ~75F for 7 days.
Bottle condition: Repitch fresh yeast and bacteria to about 4-4.5vol of CO2. Its going to have to stay in the bottles for quite a while.
This is really the only way to do a Berliner Weiss and have it come out in the traditional manner. Ive had a bunch of sour mashed beers and they just dont taste right. They either have a ton of other flavors from the sour mash or they have to big of body, not dry enough and not sour enough. People then take to adding a bunch of lactic acid. Not good.
Mashweasel: Sure. Even though I list the 'decoction' as very important, its not THE most important thing. Mash hop. Do a multistep rest. 135F x 2 hours, 149 x 1 hour, bring it up to 170F x 10min and then dont boil. Add lacto and yeast at a 3:1 ratio to start. This will give you a good idea of what the beer will be like. You will be missing a lot of the 'wheaty' flavor but if you are going to try this style, you have to get the fermentation and lacto:yeast right. MUST bottle condition. If you do it this way, let it sit in the bottle and forget about it. Then do another one with your 'fast' method. Then compare the two.
Mashweasel: Did some counts on the yeast and bacteria for ya'll as follows:
Wyeast 1007 10^9/ ml
Lacto 10^6 to 10^7/ ml
Its about 100-1000 fold difference between the two. NO WHERE near the 3:1 - 5:1 yeast.
Most people dont understand this. You will definitely need a starter for the Lacto. NO hops in the starter. I do mine at 37C shaking overnight and that works fine. If you do it at room temp, it will take longer by far.
Mashweasel: Mine usually goes into bottles after the primary so at about day 4 I like to do it. However it may have to wait until the weekend...day 7ish. You can do a secondary if you like if you find that you are getting to much dunk in your bottles. I've done it many different ways. I find the sooner I get it into the bottles the better it is. You should have a good amount of sourness going into the bottle. I've found that the sourness develops quite quickly in the bottle if you condition them warm (~80-85F) for a few weeks. It will get more sour in the bottle than out of it at a much faster rate also.
