Can I salvage a normal brew that's gone sour?

[Simonh82]

I brewed a golden ale a week or so ago and I think it has gone sour. I think it's a lacto infection but don't know enough about this style of brewing to be sure. I want to know if i should just dump it or whether it is worth bottling.

The recipe is here and I think an infected starter is to blame. I was reusing yeast from overbuilt starters. This was probably the 4th reuse and it had been sat in my fridge for quite maybe two months between brews. When I made the starter i noticed a slight tart note reminiscent of green apples but put it down to acetaldehyde as it was only on the stir plate for 24h. Also it was the first time I'd used a stir plate and I'd heard the constant agitation can lead to pretty nasty tasting starters.

Anyway the beer fermented out OK and has stabilized at 1.012 but when I tasted the sample from the trial jar it has the same slightly sour tart note. It isn't overpowering but is definitely there. To confirm, I also took a pH reading and it was 3.88, which I think is low for a normal beer.

Given that I didn't find the beer totally disgusting, could I bottle it anyway, or is this asking for trouble? I'm chilling the beer down to see what it's like cold.

If I do bottle it will the bacteria continue to ferment the residual sugars leading to bottle bombs? Is the flavour profile likely to continue to change, or is that only an issue with Brett? I don't fancy tying up my equipment for months waiting for it to ferment the last bit of sugar so if that's necessary then I think it's heading for the drain.

Any advice gratefully received.

 

[worlddivides]

So, there's no pellicle (biofilm) and no specific off flavor? (Green apples is not an off flavor I've ever heard associated with sour beers) Personally I'd wait longer to see if the flavor changes.

If it is infected and you can't tie up the equipment for months, then you should dump it. I'm assuming your equipment is glass or stainless steel, because if it's plastic, your equipment is eternally infected with whatever bugs got into your beer and you will either need to only use your equipment for sours from now on or your equipment will need to be thrown away.

As for whether you can salvage an infected brew, it's possible. It is kind of a coin toss, though, since you don't know what your beer got infected with. It also depends on the specific profile of the beer that got infected.

I personally don't think your beer can be salvaged if it is infected mainly due to the hoppiness. Your beer is 45 IBUs and uses a lot of whirlpool hops and dry hopping. Hoppiness and sour beers usually don't go well together for multiple reasons. Lactic acid bacteria (especially Lactobacillus) do not do well with high IBUs (most strains don't do well above 10 IBUs). Also, hoppiness deteriorates with time, and sours take a relatively long time before they're ready to drink. etc. I will add as a side note that there are some American sour beers that do have hoppy flavors, but they do this by having very low IBUs and very little hoppiness at first, but then they dry hop immediately before bottling. These are more of a new kind of sour beer that cannot be aged like traditional sour beers, and only adds hoppiness once all the fermentation has completed.

Just some food for thought.

 

[Simonh82]

Thanks for the advice. I tasted the beer again last night after it had chilled down to serving temperature and the taste that I perceived as sourness had largely gone.

It seems that I may have been a bit over sensitive to a combination of rather harsh hop bitterness and a bit of acetaldehyde from a green beer. I've gone ahead and dry hopped and we'll see what we get.

 

[DurtyChemist]

So how is this after a week?

 

[Simonh82]

So how is this after a week?

The beer turned out fine. I think it was an over sensitive nose detecting something that wasn't really there. I dry hopped it for a week and bottled it last weekend. I cracked one open this weekend to see how it was carbonating and it was really a very nice beer.