The last 5 I've drank from that batch but I have more but every new one I open seems to have the same problem. A week and a half ago didn't have that problem with them
After a soap and water cleaning, I use a LOT of diluted bleach solution (3 caps full in 5 gallons) with a tad of dish soap, too. Bottles, buckets, fermenters... and give them a 12 minute contact time . Rinse well or followup by soaking in just clean water. I spray Star San on everything just before used during the brew and the last thing before storing dry in a box. So far, only the tubing has been a problem and replaced it.
Problem with bleach is people tend to use waaaaayyyy more than what is needed. When I brewed in the late 80's early 90's that's about all we had, so I graciously accept PBW or oxy, and Star San. Cheap and easy.
I'm pretty sure it's bad to mix bleach (chlorinated) with dish soap. It makes mustard gas, I believe. Can anyone back me up?
You mentioned that you sanitize caps after a package has been opened. Are you using caps without sanitizing when you start with a new package?
I was told that two of the three chemicals I have make mustard gas so I do believe that. I can't tell you which two though and I'm not prepared to Google it Hot caustic is pretty bad ass so needs plenty of ventilation, I'm very careful around that one.
The one time I had a fresh package yes but that was my first brew. Wouldn't be affecting this batch. I take my caps and throw them all in ones of my mesh bags and then throw that in the sanitizer for several minutes. Then I pull it out and place the bag on a freshly sanitized surface.
On bottling day, I leave my caps submerged in sanitizer and pull them out as needed. Saves a step, opportunity of infection and a mesh bag.
Agree, folks use more bleach than needed. I like cleaning in a large sink rather than a bucket and submerge, and give some soak/contact time. That is when I'm making 5-10 gallons and don't use the PBW or Star-San and grab the bleach. Since PBW is used hot, I usually do that cleaning in a pot on the stove. A spray bottle with Star-San is a "can't live without" item and used constantly on brew day/bottling day. I think it was Nosybear who said to alternate between Star-San and PBW and I found that to fix about every problem I had with sanitation and biofilms developing.
I clean most of my tubing with a beer line cleaning brush (https://www.morebeer.com/products/beer-line-cleaning-brush-12-48.html) and then hang them in front of the (forced air) furnace vent. I think anything with a fan would work. Just need to get air flow across the tip to pull or push air through the tube.
