Got a Year to Kill...

Right on. That's just a lot of sour beer to drink.

 

Mostly true, but keep it in the back of your mind that there is still risk involved.

I have about 10 bottles of a Golden Sour that was aged on fresh peaches that smells like blue cheese & feet...

:S

 

What makes you think that it was the peaches that did that?

 

ya that seems odd. I use fresh berries all the time during peak seasons that i freeze and toss in. Never had much of an issue besides an obvious thinning of my beer from added water. Never stinky feet or onions.

 

I usually don't sanitize fresh fruit. My usual assumption is that freezing might knock-down the microbe content, but certainly no expectation of sanitation. With a mixed-fermentation I assume that all of the most notorious "spoilage" microbes are in the beer already. I'm usually adding fruit post-souring, so the pH, alcohol, lack of oxygen and fermentable sugars should limit what they could do anyway.

For clean beers, I usually do a little sanitation (StarSan for citrus peel for example). Although I assume kegging quickly and storing cold also help to limit potential issues.

 

Because the samples I bottled before adding the peaches are fine

The really weird thing was that the smell wasn't there at all either when I bottled the peach-batch, but was present after it was carbed, which took about a month. I'm hoping that I've got Brett in there and it can convert to ethyl butyrate (if I'm understanding my chemistry correctly)?

 

Fair enough. FWIW, I wasn't being a dick. It was an honest question.

 

All good - yours was a valid question!

 

You're not, but that's OK.

If you have something that smells like cheese and/or feet, you've got isovaleric acid, which, as you said, Brettanomyces can esterify into ethyl isovalerate (fruity, sweet, berry-like with a ripe, pulpy fruit nuance, artificial grape). That said, it isn't going to convert it all into said ester, because esterification is an equilibrium reaction.

The main beer contaminants that produce isovaleric acid are Clostridium sp. and they tend to come from simply not cleaning your equipment very well, but could come from "dirty" fruit. Clostridium sp. tend to lose viability in environments with a pH below 5.0, so a sour base beer with a pH in the low to mid 3s, would, very probably inhibit their growth.

That said, there are other microbes that could have produced this character.

 

But how does it taste?

 

*Golfers clap

Bravo. Beautiful dissertation. I couldn’t have said it better myself because I didn’t know any of that. You are a wealth of information on this forum. Not being sarcastic btw seriously impressed. Where did you acquire all of this knowledge School, books?

 

I have a strong science background and I read a lot. I also know where to look.

 

Internets I knew it

 

It has all the answers.

 

Ah ok... hmmm... I'm getting confused with Isovaleric vs Butyric Acids. My sense of smell isn't very good (in this case a blessing), so I'm not sure which one of these it is.

It tastes... weird... There's definitely something of the aroma in the taste as well, but if you can ignore that aspect it's not bad at all. Unfortunately you can't ignore it...