Brewed and sour-mashed a Berliner Weiss and a Gose back to back weekends a month or so back. Both beers turned out just how I wanted them flavor/acidity wise but so very cloudy I was distressed (I've entered them in a local competition next weekend). I've never filtered but I borrowed a plate filter from a member of my local club and tried the coarse pads. No difference. Well crap. Tried the "polish" pads next night. No difference. Still looks like milk. Double crap.
Reviewing my process, I realized my mistake. When I added the handful of grain to inoculate the mash w/ lacto after cooling it to 120F, I milled it first. Stupid- the lacto live on the husk, so all milling it did was add a bunch of starch to the mash after the enzymes had mostly been denatured. So my working theory is now starch haze.
LHBS has amylase powder so I stop and picked some up yesterday morning. Let the beer warm up to room temp and added 1 tsp of amylase powder per keg. I also added some to a sample pint and sat it next to a control pint so I can monitor its progress. This morning the enzyme-dosed pint is noticeably clearer. So I'm hopeful the beer will clear up enough to be presentable in 3 or 4 days. I'll let you know.
Lessons learned:
1. Filtering is dead easy as long as you have a couple of extra kegs. I will be keeping this in my arsenal in case I need it again.
2. You can't filter out a starch haze.
3. When inoculating a sour mash with malt, don't mill it. 
