Infection from a spunding valve or dirty blow off line?

General Homebrew Discussion
1

Short summary
Can a dirty blow off tube (and or spunding valve) hold enough nasties that they can travel by AIR up hoses and down into a fermenter and foul a batch of beer?

Long Version —

Hello All,
I have been chasing a wang/sour/sulfur/cider like infection for months and can not seem to stop it.
In my light lagers, that dont hide any flaws, It is really noticable.
I just made a Munich Helles and American lager and they have a cider/acid wang to them, that I want to stop.

I use RO/DI water with a bit of Acid Malt and Calcium Chloride in my beers.
I have made 20 or so batches before I switched to Keg for fermenters and did not have this infection issue with the carboys.

Bottom line is that I recently made 48 gallons of beer in 4 batches,  3 batches fermented in separate 1/2 barrel Sanke kegs and 1 batch split into 2 carboys.
All the sanke keg batches have the infection and the carboy batch does not.
All 4 batches were made with new 1st run yeast, I tasted the starter beer from 2 of them and they tasted great with no signs/tastes of infection. I dont think the yeast was tainted before it was pitched is what I am saying.

The glass carboys were clean and starsan sanitized and used air locks with starsan in them, fermented and racked into cornys like usual, no infection, it was a Kolsch that I made several times it will be great.

The kegs were cleaned with a heavy solution of PBW, 8 gallons heated to boil dumped in the keg, keg sealed up and I rolled it around and left the solution in the keg for days, a week on some of them.
I dumped out the PBW, rinsed good, looked for any crud left with a lighted inspection mirror, none found.
I rolled a gallon starsan around in them drained and filled with wort and then put on my TC setup.

The TC sanke fermenter setup is shown in the pics below.
I just bought these setups and it was the first time using them, before I was just using the standard sanke spear and modified sanke keg coupler with the same liquid and gas hoses.
I bought these TC setups thinking the coupler/spear was the infection problem… but it is not or at least is not the whole problem…as I have the infection with the new hardware.

All liquid side hoses were soaked in starsan and was put together with starsan sprayed everywhere, it was the first run with these hoses.

On the gas/blow off side I used a new hose that goes from cam lock to QD to QD to hose to spunding valve.
I did this so I can take off the gas side/clean and re use spunding valve when I pressure fill the corny kegs.
I dont have a good way clean the spunding valve assembly and have not pulled off it all apart to clean/sanitize this valve/hose assembly. I dont see any gunk in the hose though.
I was thinking though, maybe incorrectly, that no nasties would go airborne, up the mess of hoses and back down into the fermenter… is that wrong?

So the problem with my infection seems to be the keg fermenter or gas/blow off side/spunding valve assembly.

I will make a batch of beer soon and split into a carboy and a keg with a stopper/air lock to try and isolate the issue.

In the mean time, anyone have an opinion on what I am doing wrong?

thanks for your help
Kevin

Pics of my setups

https://lh3.googleusercontent.com/-9BIFr7d04uw/U7QoUeHhmeI/AAAAAAAAAz0/4Ax2rjIt8xk/w1580-h889-no/20140701_234518.jpg

https://lh6.googleusercontent.com/–QrQZDj2lo8/U7QoZz12JQI/AAAAAAAAA0E/oL1S_xwL5qg/w1580-h889-no/20140702_000103.jpg

https://lh6.googleusercontent.com/-dwO7626GBYo/U9J0iE0S4nI/AAAAAAAAA1U/fonXwUhVU28/w500-h889-no/20140724_225801.jpg

2

Hmm, I’d be hesitant to say it’s coming from the blow off side, however, I don’t do pressurized fermentations. I use ball lock kegs to ferment 4 gallon batches and never sanitize my blow off tubes (gas disconnect with tubing going into jar of sanitizer or water). Although maybe I should… Perhaps you aren’t getting your spears clean enough? I assume you’re running cleaner and sanitizer through the whole system? I don’t I don’t really do the cleaner part for my fermenter kegs, just rinse well, use a dip tube brush, make sure poppets are clean, then fill part way with sanitizer, pressurize and let sit like that until I need it again.
I would say maybe post your question on the pressurized fermentation thread on Homebrewtalk to see if it’s possibly coming from the blow off side.

3

I would suspect the following places:

  1. The threads of the blowoff tube. I would boil that guy before using. Every time. Actually, I would just go with a welded/TC model with no threads. Threads and teflon tape are not sanitary and WILL hold bacteria.

2.  The TC gasket. Is it black (rubber) or white (Teflon)? Both will eventually harbor bacteria and need to be replaced. They also need to be sanitized. Teflon can be boiled, rubber cannot.

  1. The plastic hose barb. You should replace it with stainless, but either way it should be pulled off the tube and sanitized. Soaking the assembly in StarSan won’t sanitize the area between the barb and the tube.

  2. The gasket for the flared fitting. Take it apart and sanitize it. Also, if you move this rod up and back down into the fermentor, you could be exposing the beer to microbe-laden air.

  3. The plastic QD and picnic tap. Both are notorious for harboring bacteria. Get rid of the picnic tap. Either run sanitizer backwards through the keg filling assembly or fill through the keg lid (technically ‘open’, but less places for bacteria to hide). If you really want a ‘closed’ system, swap the plastic for a TC connection (hose → barb/TC connector → TC welded onto keg lid).

So there you go. There are definitely less convoluted setups for pressure fermentation/transfer, but looks like you’re invested.

4

My question here would be do you have any beerstone in that keg? If yes it is almost impossible to sanitize it.

As long as you sanitize your tubing it should be OK.

5

For these last 3 keg ferments the hardware was new and/or tubing was pulled apart, old edds cut off all soaked in PBW and starsan and resassembled.

I assume soaking the parts in PBW then rinse and re assemble while spraying starsan is sufficient to clean/sanitize?

1 - Nice ideas I will definately pull this apart in future brews
2- White silicon
3 - OK - I will continue pulling the hoses apart and looking for a better solution
4 - If I starsan the dip tube before I move the tube down wont that suffice?
5 - If I pull the ball lock QD and picnic tap apart and soak and sanitize will this suffice?

I am looking for a better way… let me know if you have a better way to ferment/transfer.

thanks for the responses
Kevin

6

I dont see any beer stone or left over crud in the keg.
I did use one previously that I did see what I believed was beer stone and stop using it… but my infection still persisted.

In the future, I am planning to put 8" TC fittings on the bottom of the kegs so I can easily clean and see into them.

thanks Kevin