Strange filtration issue

[Lighthouse]

This is frustrating. We have a pair of 100hl conical unis with 70 degree cones, removable dual outlet assemblies (bottom outlet and fixed stand pipe outlet) and dedicated recirc legs for the distribution of finings. The usual procedure is to harvest the yeast we need a few days after crashing, dump the rest, fine with geletin, milk off the remaining yeast for the few days, and then filter though 4x16" Pall SupraDisk lenticular cartridges. With a gentle backflush afterwards and storage in a KMS solution, we can get 3-4 runs out of a set...

...unless we're using Wy1272. With both our house yeast and 007, we can eject almost all of the yeast and the beer is almost bright going into the filter for the entire run. With 1272, the beer looks bright, but throughout the run, big slugs of yeast will go forward and blind off the filter half way through. Where is the yeast coming from and how is it finding its way over the top of the stand pipe when there is no yeast at the bottom of the cone? And yes, we know there is no accumulation of yeast at the bottom as any attempt to eject from the bottom outlet produces beer. Is 1272 super sticky and it sort of peels off the cone and finds its way to the raised outlet? Annoying. Don't want to have to use a different yeast.

[Trickster]

Krausen?

My guess would be that you are getting a large krausen inside the fermenter during fermentation that produces a yeast ring at the level of the beer. As you filter the level of beer drops and that krausen ring no longer has any "support" from the beer and falls into the beer in the tank and will eventually get sucked up and sent into your filter. Maybe try a bag filter prior to cartridge filter if you think this could be the problem. One way to check would be to open up the tank after filtering (before rinsing) and look at that ring in the top of the tank and see if there are any missing chunks or area of the ring. Cheers.

[wailingguitar]

I think Trickster is on the right track there, I have had similar things happen to me.

[Lighthouse]

Thanks guys, that sounds very plausible. I'll check inside the tank after the next run. Might be time to start thinking about antifoam for that particular beer.

[MikeS]

It's been a long time since I've used 1272 yeast, and I've never used it in a production brewery with CC tanks, but I seem to remember that 1272 was a bit "sticky."

What may be happening is that there is a significant amount of yeast stuck along the inside of the cone. Even after cold conditioning and yeast drains, there will always be some yeast stuck to the inside of the cone, and that yeast has lots of CO2 in it (held as bubbles in the slurry.) As you pull beer out of the tank, the amount of hydrostatic pressure holding that yeast where it is lessens, and the CO2 bubbles make the yeast buoyant and big chunks of yeast float up and you see them as slugs through the filter.

At a large regional where I used to work we would actually open up the tanks during filtration (to visually gauge the turndown of the racking arm) and we could see big slugs of yeast bubbling up. We were using DE, which is much more forgiving as far as big slugs of yeast go.

I don't see any way to avoid the situation, unfortunately... You may just have to suck it up (pun intended) and use a pre-filter or just plan on a breakdown when filtering the 1272 beers.

Best of luck!!

-Mike

[Lighthouse]

Thanks Mike

That sounds likely too. We carbonate to 2.5 volumes in the conicals with a spunding device at the end of the ferment, and during filtration, the CO2 reg supplying head pressure to the tank is not able to keep up. A drop in tank pressure, both head and hydrostatic, may result gas beak out within the stuck yeast, which may cause it to 'raft'. I have another tank ready for processing next week; I will try dumping the head pressure now and then making sure it's screwed up high on filter day.

[Lighthouse]

And yes. It would be nice to move away from 1272 due to the difficulty we have with it, but 007 doesn't produce the dry, crisp and brightly hopped beer I'm looking for, and all of the other local brewers are using 001/1056 and I don't want my beer tasting like theirs.

[Trickster]

Filter Balance Line

Do you use a filter balance line between the tanks? This could help with keeping pressures even and you don't have to worry about introduction of O2 in the tank being filtered from, less O2 = Longer shelf life. Basically you are filtering into a tank under pressure (I usually start at 15 PSI) and I purge out the O2 with the CO2 in the Brite tank. I then connect to the fermenter and open both valves and "balance" the tanks. As the brite tank fills the CO2 pressure will move into the fermenter. This could work to try and eliminate that possibility. If you are really wanting to keep your beer unique in your market I would try and do everything to keep it that way including looking at a pre-filter for this particular beers filter day. Cheers.

[Lighthouse]

Thanks Trickster.

This time I de-gassed to about 10psi four days before filtration, yeasted-off every day, gasses up to 20psi before running to prevent gas evolution in any yeast that may be stuck to the cone... but still no luck. Big slugs of yeast still going over the stand pipe and forward to the filter. And it is yeast and not detached krausen ring. Bugger. Goodbye 1272

[Zucker Bee]

We crash to 10c for a day or two, then "bomb" with CO2 from the racking arm, which causes the yeast rings or any on the sides to drop into the cone. But then, we don't filter these beers made with WY1272

Ben

[Lighthouse]

We seem to have this sorted now. The problem seems to have been uneven gel distribution. We used to recirc at a good clip and then introduce the fining quite quickly, with the idea that the gel falls through the liquid column "like a net". It doesn't. Now we re-circ gently and let it run for at least an hour, ensuring that we get a couple of complete exchanges. Gel is introduced very slowly for the entire duration of the recirc. Now the beer drops bright and we can eject smooth, high-solids material that isn't sticky or clumpy. Today we pulled down a tank in two hours, recovering 2x 44hl in BBT from 94hl of run-in wort.