Beer changing character in the bottle

Had what I thought was a great brew, the beer tasted exactly what I was looking for after 2 weeks aging in the bottle, now 5 weeks after bottling, the beer is turning quite bitter and undrinkable. Feel confident my sanitation was good, bottles cleaned and run thru the dishwasher sanitizing wash, then immeresed in star san for 5 minutes the day before. Never had this problem before and my routine is pretty much the same. During the brew process, everything seemed to hit the Beersmith targets, except I ended up with .5 gallon more in the brewpot than target. It is a simple all grain Am wheat.
Any thoughts? I’ll be bottling a speckled heifer this weekend.

Thanks
Sailfast

Rapid changes in the beer often are caused by an infection. And “bitter and undrinkable” sounds to me like you’re losing the body of the beer, another sign on a possible infection. Are all the bottles the same? Has the carbonation increased?

+1, that’s what it sounds like. Your beer should be tasting better with time, not worse.

Sometimes despite our best efforts, something floats in at the wrong time and an infection can occur. If you’re using a bottling bucket, take the spigot apart and soak it good. Doesn’t sound like a process problem, and unless the yeast is dropping and you’re just getting more hop flavor at this point, I would concur it could be infected. Usually you’ll see a little scum form at the top of the bottles when theres an infection, but not always right away.

Ok, some good news, the “problem” seems to be in 3 bottles, the rest are good, really good. They were among the last ones bottled. We try not to siphon any trub into the bottling bucket, maybe some got in and there was a concentration as I imagine it would settle in the bucket, Thanks to all that commented, this is a great place to information.

Sailfast