Flat vinegary porter

I bottled my first homebrew, a porter extract kit, about 1.5 months ago. It only has minimal carbonation, a slight hiss when I open it and no head. It also has a strong vinegary flavor. The carbonation level has remained static since i first tried it 2 weeks after bottling, but I think the vinegar flavor has gotten worse if anything.

I can't think of anything I did wrong during the brew process, and my 2nd beer (using the same equipment) does not have either of these problems. Does anyone have a diagnosis of what happened to my porter?

Vinegar is commonly associated with a bacterial infection. Hard to pinpoint the source, but it could be anything from the fermenter, to bottling bucket, to bottles themselves.

How did you sanitize everything?

Extract kits sometimes have a sour tang to them, which sucks but is normal/not your fault. Does the vinegary flavor actually taste/smell like acetic acid? Is it sour? If so, you may have an acetobacter infection. Clean, sanitize, avoid air contact &ct. for future batches.

Carbonation. How much priming sugar did you use, and what temperature is the area you're keeping the bottles at?

Could be bacterial but..

What priming sugar did you use? Whenever I use DME for bottling, it takes significantly longer to carb up (like 2 months instead of 2 weeks), and there's a green taste to the beer that takes a while to go away (not vinegar per se, but definitely sourish). It goes away after a while but takes time

I sanitized everything with starsan including the fermenter, bottling bucket, bottles, caps and any tools used in the process. There were no signs of infection on bottling day, and the beer did not have a sour taste at that point either.

The sour taste is certainly more than just a tang, it is pretty undrinkable.

I used the 3/4 cup of sugar that came with my kit to bottle. Poured it in the bottom of the bottling bucket and let it swirl in as I siphoned from the fermenter.

i am having a similar problem with a stout which has been bottled for a little over a month now. weird thing is that they carbed up fine, there is no sign of infection and its all in the aftertaste. i was going to let it sit another month.

Did you boil the priming sugar?

Well, let's not jump to any conclusions just yet. How many bottles have you tried? It could be an issue with some bottles and not others. Don't dump anything until there's an absolute certainty.

I've had one infected batch. It didn't show up until about a month after bottling.

So far as carbonation goes, the temperature of the bottles would be the first thing to check. They should be at about 70*F, ideally - at least, if they're being stubborn. But if we're dealing with an acetobacter infection, that could be stopping the yeast as well...

I have tasted 4 bottles now. The first one 2 weeks after bottling, and the others spaced relatively evenly thereafter. The sour taste was pretty subtle on the first taste, but is now quite potent.

I didn't boil the priming sugar itself, but I did stir boiling water into it before dumping it into the bottling bucket.

The beer fermented at about 65*F and for the first few weeks was siting at or below that number in the bottles. When there was only minimal carbonation by the third week, I moved the bottles next to my dryer, so they have been warmed up a bit. My second batch (an IPA) carbed-up fine in under 2 weeks sitting right next the the porter.

Edit: questions been answered, and I was wrong anyways

Yeah, it really sounds like you have an infected batch. Don't pitch anything yet, but brace yourself for that possibility.

On the bright side, it can only go up from there. Infected batches are fairly unusual; if this does turn out to be infected, at least you got it over with on your first batch. For some reason, most people I talk to have had exactly one infected batch in their brewing careers. Myself included.

IMO - it's a clear line between infection and off flavors.

If you have an infection you will know it because the bottles may gush and the beer will be unspeakably terrible.

If you have off-flavors, it may get better with time but it's not guaranteed.