Boiling Sour Beers - Is DMS ever an issue?

i've got nothing but conjectures, but the current thought is that SMM mainly stays as SMM if the wort is not boiled, not converting to DMS (or enough to pass the perceivable threshold to most people). So actually a short say 15 minute boil maybe more harmful than a no-boil. I covered it very briefly in an article i did earlier this year in the section on mash hopping:
http://byo.com/stories/issue/item/2958-pre-boil-hopping
But again, I've got nothing put ideas without solid proof. Maybe someone else does though...?

 

Made two berliners with 20 minute boils. No DMS at all.
Third one the same, still fermenting but I took a sample yesterday and it tasted great, no DMS.
As to why, beats me...

 

DMS can be a byproduct of bacterial contamination, but I've never gotten it from the microbes in a sour beer. With the low pH and minimal dextrins remaining, there is a much lower risk of unwanted microbes causing problems in a sour beer than in a clean beer.

As for DMS from the malt, I've never had an issue. DMS is more volatile at warmer temperatures, so it is really lagers that have the biggest risk (especially considering how long most sours sit). I’ve done several no-boil Berliners (bringing the temperature up the 210F or so) and never tasted DMS, or had judges note it. Usually I get sort of a raw doughy flavor that is quite pleasant in a beer with so little malt.

 

DMS doesn't seem to be an issue... diacetyl on the other hand does.

 

I've never had a diacetyl issue with sours. Some lactic acid bacteria (Pediococcus most notably) will produce plenty, but Brett always cleans it up for me. Wouldn't be related to no-boil anyway.

 

Crooked Stave has had an issue with it recently. I'm not positive, but it seems to happen on bottle conditioned beers exclusively.

 

I recently did a non-sour mash Berliner with a friend and Fermented with Brett C. After bottle conditioning it acquired a popcorn-like flavor I was told was Diatecyl. I didn't taste it before bottling. Maybe something to do with Brett only fermentations?

 

Not from the Brett, probably the Lacto.

 

This is a relatively common off-flavor in your sour beers (I call it Cheerios, other people taste plain unbuttered popcorn). I suspect that it is a Brett intermediary product. The important thing is that it will go away given a couple months of warm conditioning.

 

The bad part is between the bottle conditioning sugar additions, along with copious amounts of dryhopping, a lot of the American wild ales have a small window of amazingness...

 

I find pitching rehydrated wine yeast can help shorten/mellow the issue, taking those sugars away from the wild microbes.

 

Crooked Stave has only ever bottle conditioned the really small runs to help carb the beer. Otherwise the main stuff (Surette Etc) is not bottle conditioned.

 

It's popping up in Batch 60 as well as origins.

 

That's possible. However, neither of those beers were bottle conditioned.