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 ---
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
Pics of my setupshttps://lh3.googleusercontent.com/-9BIFr7d04uw/U7QoUeHhmeI/AAAAAAAAAz0/4Ax2rjIt8xk/w1580-h889-no/20140701_234518.jpghttps://lh6.googleusercontent.com/--QrQZDj2lo8/U7QoZz12JQI/AAAAAAAAA0E/oL1S_xwL5qg/w1580-h889-no/20140702_000103.jpghttps://lh6.googleusercontent.com/-dwO7626GBYo/U9J0iE0S4nI/AAAAAAAAA1U/fonXwUhVU28/w500-h889-no/20140724_225801.jpg