Can a sour turn non-sour?

I currently have a blackberry sour that is almost a year old. At the six month mark, I checked it, and it had a pleasant sourness along with a light blackberry finish (I only used 8 lbs in a 5 gallon batch wanting just a hint of flavor). I checked it recently and the blackberry hint is there but there is no perceived sourness. What gives?

For the record, we pitched about 10 different dregs into this at the start just as a fun project.

I don’t know, but sometimes when a beer starts to oxidize it gets a caramel-like flavor, which might balance the sourness.

Still a solid pellicle on top, and definitely not oxidizing.

You can always go with a Solara…blending with newer sour beer may hit that “sweet spot” (pun intended, obviously).

Good luck with your beer - those sours can be elusive!

The issue is, it was sour. Now it isn’t. I’m trying to understand the phenomenon and why it happened, along with if it will turn again

A sour is its own thing as I see it.  Mellowing of any beer can change the flavor profile.  By blending you can achieve more sourness, but my guess is that once that lactic bite has mellowed out, it won’t return as to the original beer, but you can also try some Brett to get funk - not sour, but more complexity.

Of course adding straight lactic acid is another alternative, but go easy on a sample before extrapolating to the whole batch…  Good luck.

I’ve read from at least one yeast wrangler (bkyeast.wordpress.com) that Brettanomyces can break down some acids to make them less acidic.  In geenral, they are very good at making their environment suitable for the long term.  Perhaps you have a Brett species or strain from one of those bottles that is particularly good at doing this.

I’ve seen Brett do weirder things, that’s for sure.

Dan, so you are saying brett can “eat” the sourness?

Has anyone played with the cheater sour method (lactic) ? Like, a cheap easy sour (fill in the blank) maybe a light lager? Redneck Berliner?

This was all bugs, no cheater here.

Over a very long period of time a sour beer will get less sour. Not the same as a clean beer but definitely not the biting acidity of a young sour beer. Brett can metabolize some acids as well as ethanol. However, that process is long. Think years, not months. When I bottled the three year old portion of the gueuze I blended in December I was surprised by how not sour it was although I bottled a portion of that beer when it was a year old and that portion is still sour.

The lactic acidity will smooth out with time and I usually find that happens around the 12-18 month mark. That may be what happened to OP. I’d want to know more about what the beer tastes like besides blackberry to try to diagnose what’s going on. It may also be the case that the blackberry went in and the sugars were consumed by brett faster than any lactic acid bacteria so no additional acidity was created. That would give you a beer with the same volume of lactic acid but less lactic acid compared to the amount of ethanol and flavor compounds in the beer, making the acidity less prominent.

I’m wondering if any of the bugs can perform a malolactic fermentation. Blackberries contain quite a bit of malic acid, which is a lot more tart than lactic. If there was some malolactic fermentation, then the sourness would smooth out over time.

Can you Elaborate on this? Never heard about this before…

Malolactic bacteria turn malic acid into lactic acid. Lactic acid has a softer perceived acidity than malic. It’s often used in wine and traditional cider. The bacteria are common of fruit, but I don’t know if they can survive hops. Never heard of malolactic fermentation in beer before.

This post peaked my curiosity on the matter of Brett being able to break down some acids.  I would imagine that some Bretts are more aggressive about this than others?  For example, Jolly Pumpkin sours are generally not very tart (say compared to Sour in the Rye or La Folie).  I don’t have any experience with JP dregs, but I’ve heard Ethan Tripp talk about how their Brett is so aggressive that he keeps those dregs separate from other dregs beers.

Sometimes pellicles serve to move O2 from the head space into the liquid to for the benefit of the pellicle forming organisms.

But it could be conversion of acids or something settling out over time that is altering your perception.

I would assume just as a matter of genetic diversity some strains are more aggressive than others. However, my understanding is that like sacc, brett will metabolize available food sources in a particular order. That usually begins with consuming sugars and then starches before scavenging for other food sources like ethanol and whatever else it will consume. So if that is the case then I would expect the ethanol and acid metabolism will always occur with time and at least some of that metabolism may require a certain level of oxidation.