Originally Posted by TheBeerist
Probably. The bacteria (lacto or more likely pedio) and/or wild yeasts that are infecting his beer work slowly. Which is why you don't taste them at first, and why they are getting worse over time.
It's definitely a sanitation issue that you're having. Still waiting for more details as to your bottling day. But it sounds like the other guys in this thread have it figured out.
I'm sort of hijacking this thread as I have the same issue.
Break down on cleaning;
I wash all my stuff in dish soap and water, then towel dry it. I take the little filter off the end of my auto siphon and take the inner tube out. I take the tubing off the siphon and wash everything apart.
Then I rinse it all in iodiphor.
I wash bottles in soap and water, rinse, then fill them and let each sit for a few minutes full of iodiphor, poor it out and start filling with beer.
I do not use a spigot to fill but use my siphon with wand.
I don't see how it could be dirt bottles as after three week with 25 remaining you'd think I got at least one or two clean bottles.