I have now had 3 batches with a wild yeast (I think) infection in the last 3 months. This is driving me crazy. Between that and a batch of Helles Ale ruined by peach esters from US-05, I feel I no longer know how to brew. It’s very frustrating.
Regarding the infections: the first two had one thing in common: pitching slurries (there was a forth sometime last year which was infected after pitching a slurry). I thought maybe I had some bad sanitation practices in my slurry storage. I recently decided to stop saving yeast for a while and just pitch fresh each batch. On my latest batch I pitched a new pack of MJ M44. Now that batch is infected. That blows up the slurry theory.
Symptoms: bandaid/phenolic, cloudy, krausen slow to drop. The symptoms are the same every time. I have let these beers age and it’s not some mystery flavor that ages out. The bandaid flavor sticks around. I think it is wild yeast.
I had three clean batches in a row (one sucked due to US-05, but, that wasn’t wild yeast). I thought I was back on track.
After the 2nd infection, I cleaned the whole brewery with high test bleach water. I soaked my fermenter with high grade bleach water and then sanitized With iodophor. I had three good batches in a row.
For this last infected batch: I used Starsan to sanitize the fermenter. I used a brand new bucket. The lag time sucked (60 hours until a krausen).
Beers from 3 fermenters have been infected.
I taste the infection when checking gravity while the beer is still in the fermenter. So this is not a hose problem picked up during transfer to keg.
I have three theories:
1. My brewery is in a closet. I brew outside. But, I ferment, serve, and store my equipment in an 8x8 closet in the garage. Could spillage and time have led to a large wild yeast concentration in this room? Could there be yeast on my tools or in the air?
2. My fermentation chamber may harbor wild yeast. My last non-infected batch had nasty growth on the fermenter spigot. That batch wasn’t infected but I was alarmed. I cleaned the inside of the fermentation chamber with high test bleach water before that batch. I cleaned again after.
Dark spots on spigot are some growth. It was white going into the fermenter. This batch was not infected and I have not reused that spigot.
3. I move beer from Grainfather (GF) to the fermenter via pump. Maybe that pump or hoses are harboring the infection. Could it be that I am not recirculating long enough at boiling temperatures before moving the beer to the fermenter? I don’t think this is the case. I run the pump recirculating through the chiller during the boil for at least 30 seconds to one minute. The chilling seems slow, so the beer in the kettle stays above 140F for at least 5 minutes after starting to recirculate. Am I doing this wrong? The temp in the GF drops pretty slowly. Maybe the temp in the recirculation loop drops faster than I think and I have something growing in there? My GF is relatively new, so, I am still learning. But I have had at least 4 non-infected batches with it. But, all 3 infected batches were brewed on the GF. Also, there is no pellicle. I would expect bacteria and a pellicle if the hoses or pump were dirty.
Plans: I plan to empty the brewery for a deep clean. I also plan to use iodophor for fermenter sanitation. I plan to recirculate through the chiller for 3-4 minutes during boil. Not sure what else to do.