Good turned bad

I made my first brew about 5 months ago using only a can of extract. It was terrible but my pride wouldn't let me toss it, so I drank it.. I added some stuff to my next batch:
This is a very strong pure malt stout in the Guinness tradition

with plenty of body and flavour.(7.5% Alcohol)

1 can of Coopers Stout

1.5 to 1.7 kg Light Dry Malt Extract

Note: Fill your fermenter to the 18 litre mark only.

If you have any spare yeast, you will get a better result

by using 2 identical packets of yeast instead of 1.


I had one about two months after bottling and it was great. I then went back to drinking batch #1 to get rid of it.Now, a month latter batch 2 has become vinegary. It continues to foam up the bottle neck for 20 minutes after uncapping. Any ideas as to what went wrong? Thanks.

Vinegar taste is normally a sign of infection and if it is foaming in the bottle like that then this is most likely the case. Acetobacter is the bacteria that creates acetic acid and causes this flavor. It can be desirable in low levels in beers like Flanders red and Oud bruin but too much and it quickly becomes offensive. Sounds like this may have been a sanitation issue. Double check your process and try to pin down when this might have happened because it is possible for acetobacter to stick around in fermenters and potentially infect future batches

This is interesting because I posted a question about this the other day but didnt get a response. I had a batch of Pale Ale that was pretty good at first but after about about 1 1/2 months I noticed a vinegar taste. I don't have any foaming or any other signs of infection; just vinegar flavor.

Can Acetobacter take time to make itself known? The vinegar taste was not present until 6-8 weeks after bottling i my case.

Col_klink said:

This is interesting because I posted a question about this the other day but didnt get a response. I had a batch of Pale Ale that was pretty good at first but after about about 1 1/2 months I noticed a vinegar taste. I don't have any foaming or any other signs of infection; just vinegar flavor.

Can Acetobacter take time to make itself known? The vinegar taste was not present until 6-8 weeks after bottling i my case.

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Many of the spoilage bacteria, most of which work in an anerobic environment, take time to make themselves known. That's why intentionally soured beers take longer to develop. My very first homebrew was infected with a (most likely) lactobacillus, and got more sour as the weeks went by. It also developed a ring arount the neck of the bottle, a good sign of infection.

I actually have a 4 liter aspirator bottle that I keep apple cider in to turn into vinegar, with a "mother" that is probably acetobacter.

Thanks to all responders.I don't know how I could be any more careful with sanitation.I starsaned everything.I used store bought spring water.I guess I'll have to try harder.Thanks again.

mak104 said:

Thanks to all responders.I don't know how I could be any more careful with sanitation.I starsaned everything.I used store bought spring water.I guess I'll have to try harder.Thanks again.

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If everything was sanitary, then you may need to look at some of the processes. For example, when you're chilling, is the pot opened or covered? If you rehydrated the yeast, was the water boiled first then cooled, covered. Did you cover the yeast while it was rehydrating. Did you cover your bottling bucket while you were bottling. I'm not saying you did any of these things wrong, but any time you got infection, it came from some where. Like those damn fruit flies!

Did you clean as well as star san? Some think star san is a cleaner and a sanitizer. It only works if the stuff is clean first (esp bottles!).

Absolutely.I obviously missed something though.I starsaned the can opener, bottle caps.Hydrometer.Of coarse the bottles and fermenter.The bottles were new(glass). I ran them thru the dishwasher and then starsaned.Maybe that's not good enough?