Aaagghhhh!! Help with my filter problem!

[tsmack]

Hi all,

I've got hazy filter #5 running through my 40 plate 40cmx40cm plate and frame filter press.

It is NOT:
-pads put in incorrectly. Trust me.
-bad pad lot...I share orders with other local brewers who have no problems from this lot
-yeast mutation....happening across 4 strains, all 1st-to-4th generation
-high protein content in new barley lot. Again, other local brewers using same supplier.
-mash technique, boil, cold stabilization post-ferment, etc....nothing has changed in our SOP over three years and suddenly every filter is hazy.

What I think it IS is f@cked-up filter plates or gaskets that are cracked or something. I've been talking with Dave at Glacier Brewing who had the same problem a few years back and he replaced all the plates and gaskets and the problem went away.

So here's what I'm asking for help with: can anyone out there think of a way to pinpoint which of these plates is bad so I don't have to buy 40 new plates at $60 a pop just to replace one bad one? I really can't think of how to locate the bad plate(s)!

Any help appreciated!!!

Taylor Smack
Blue Mountain Brewery

[Sauce]

hmmmm...maybe a automotive crack detector dye? think its used for air conditioning and collant leaks. I think its a spray on application and florescent under black light?

....could be wrong, been 20+ years since I delivered the stuff for Napa;-)

[burcher]

is it possible to blow co2 or compressed air through it while holding it under water - like the way we used to find leaks in our bmx bike tubes - looking for the bubbles?

[South County]

Check and make sure you don't have a two-way plate in that is bypassing your filters pads (plug missing), I'm sure you know your filter but just a thought. If your getting flow then your not blinding from yeast. If its not bypass, it seems it would be permanent haze or cracks in the plates/gaskets, however if you can't visibly see the cracks you should be getting somewhat brite beer. Can you borrow a filter press to filter batch and see if it it actually you plates/gaskets or not?

Burcher: Most all filter presses leak or permeate beer thought the pads as you filter, hence the drip pan with tri-clamp fitting on most. So submersing in water would look like an aquarium aerator probably. The AC detector dye might technically work but would have to be put through the filter and then pressurized, however I wouldn't mix that dye with a food production machine, its petroleum based.

[tsmack]

All,

Thanks for the responses. I am borrowing 20 plates each from two different local breweries and will be using my chasis and my gaskets. If I have a bright filter I know at least the problem is messed up plates. If not, I move on. My confusion now is this: I don't understand how a plate CAN be broken. I even talked to the owner of a filter-pad company, and he assures me the plates are really just there to hold the pads in; sure they have the handy weep-holes and the neat grid pattern to make the beer crawl across the pads and seep into the alternating pad's weep holes and out through the path created by the gaskets, but he (and I) just don't see how a crack or anything could cause the beer to bypass the pads. And after visual inspection I see no cracks anyway. Totally stumped. I should also mention that there really was not significant yeast build-up on the pads, so it does look like some sort of bypass is happening.

As far as a two-way plate, I don't have any so that's not it, but it's a good suggestion.

I'll post as we continue honing in on the problem. Any other wild theories welcome...

Taylor

[Guestimate]

Taylor,
Have you checked the bubble point before and after filtration? This would tell you for sure if you filter is structurally sound from start to finish. I am not sure what the median pore size is for a #5 filter, but generally I look for a minimum bubble point of 35 psi for a 0.5 micron filter. Your filter supplier should be able to tell you what psi to look for when conducting the bubble point.
As for the broken plate. I am assuming you have a filter with the black noryl plates that have a small removable plate at the inlet and outlet? I knew a guy that lost the hardware (small screw) that holds the little plate in place and opted to run with out the little plate. Part of his start up was to backflush all liquid out of the filter with CO2 immediately before sending beer. He experienced the exact same problem. We figured out that the filter pad was stretching during the CO2 backflush. The pads did not tear so it was not visible and when he ran beer forward, it push the pad flat so we could not see anything unusual when we pulled the pads. We found the problematic procedure by performing many bubble points to isolate the point of failure.
My two cents.

Kevin

[tsmack]

Thank you everyone for the insight. Just ran 15bbls of young hefe (to become kristallweiss) through 40 borrowed plates. Guess what? Crystal-freaking-clear. I don't understand it, but somehow something is wrong with one or more of my plates.

Taylor

[ParishBrewingCo]

Well at least you can rest easy that you've found the problem! Congrats! I would be losing sleep until I tried those loner plates.

Andrew