Sour Yeast Strain.

Yeast will convert diacetyl (butane 2,3 dione) into one thing. Acetoin. Then 2,3 butanediol.

As Brettanomyces is yeast, that's the only thing that will happen.

Doing that would prevent diacetyl production, one would think.

 

Agreed.

There are some very novel Saccharomyces cerevisiae strains that can produce lactic acid, but that certainly doesn't usually happen, and Brettanomyces species only produce acetic acid in the presence of oxygen, which isn't how you want to increase the acidity of your beer.

Lactic Acid bacteria, namely lactobacillus, pediococcus, and oenococcus sp., are where you want to get your sourness/tartness from.

 

Unless you crash it mid fermentation. This is what Drakes does and they said it creates a lot of Diacetyl which is what they’re going for??? They like the character that their culture turns the diacetyl into? Not sure if NB does that but couldn’t a warm fermentation with lager yeast create more sulphur which Brett can convert into something more interesting. Can’t remeber where I heard that, could be wrong.

 

Or possibly that they like what said active culture does in their beers. Active yeast metabolize diacetyl, but they also do other things, like create esters and phenolic compounds.

Although sulfur based compounds, like mercaptans/thiols, can be interesting, creating more H2S isn't going to make your beer more interesting. It's just going to make it stink until your yeast metabolize it.

 

First time sour brewing is difficult enough, a little insurance never hurt.

 

Upon googling found this about Brett and Diacetyl...

——————
Brett goes through the same diacetyl-->acetoin-->butandiol but there is an important difference. Brett is subject to what’s known as "Custers Effect", which essentially means that the rate of glycolysis (sugars down to the level of three carbon compounds) and fermentation is *increased* in the presence of oxygen or alternative electron acceptors (Though with enough oxygen you run into issues of acetic acid production, low EtOH titer, and poor attenuation...but I digress. #brettsnotsourbro). As I inderstand it, the conversion of diacetyl-->acetoin-->butandiol stimulates the activity of Brett due to this effect. Indeed, acetoin has been used in a number of publications to stimulate Brett to look at fermentstion patterns, etc. Sacch is not subject to this same type of regulation. So an argument could be made that Brett is better suited simply due to the stimulation that these compounds provide.

 

I’m no scientist so this could be off base but can’t sulfur also act as an antioxidant is some manner? Elevated levels of it could maybe protect against the onset of too much acetic acid from increase O2 exposure in battles or foeders? Or am I way off in that regard?

 

Custers Effect, stated simply, is that Brettanomyces species both grow AND ferment better in the presence of oxygen. Saccharomyces species grow better in the presence of oxygen, but ferment better without it. This is called Pasteur Effect, which gives us the alternate name for Custers Effect . . . Negative Pasteur Effect.

This has more to do with fermentation dynamics than it does with the enzymatic strength of the genus, though. In regards to esterase, decarboxylase, or reductase enzymes that they use to create flavor and aroma active compounds.

 

I cannot say that I've heard of sulfur compounds working in this fashion, but, then again, I'm not a chemist either, so . . .

 

It just struck me as odd that they use a lager yeast fermented warm for their primary fermentation in stainless. Is it just for the ester production and what the Brett does with those esters or is it for another reason? Supposedly lager yeast produces twice as much SO2 as ale yeast and ideal ferm temp for SO2 production in 16c. SO2 is definitely an antioxidant so maybe it could help prevent acetic acid production? Or at least too much acetic acid production?

 

A well known benefit of a little Sulfur in lager brewing.
https://www.morebeer.com/articles/sulfur_compounds_in_beer

 

Awesome refresher article. Thanks for posting it. The important bit is here:

A small amount (0.5–20 ppm) of sulfur dioxide is also formed during fermentation (especially lager fermentations); however, as long as the level is subthreshold, its antioxidant power improves flavor stability (4) with no detrimental effects. Remaining free molecules of sulfur dioxide in beer are generally scrubbed out during the fermentation.

Emphasis mine, because you don't want large/increased levels of sulfur in your beer. You want small amounts. So, if you're smelling or tasting it after fermentation is complete, that's too much.

 

In Germany you often get a little whiff of sulfur when you raise the beer up to your nose. It goes away quickly. We are sensitive to sulfur, and can pick it up at very low levels.

 

As long as it off-gasses quickly, I don't see a problem with this character.

Is that the royal "we"?

 

If said beer is going to be aging in wood for a minimum of say 9 months any sulfur will be gone but if an increase in it can help to delay the onset of acetic acid production or at least keep it to lower levels I would think it would be good thing??? Since Peter Bouckaert came from Rodenbach I would assume they use a lager yeast as well.

 

If you're worried about oxygen ingress during aging, I'd think sulfur content of your beer would be on the low end of things you'd do to make sure it's at a minimum.

That very well may be. Anyone know the answer to that?

 

third person plural? As in we humans.

 

???

That’s one of the biggest reasons why they’re aging in wood... for some
O2 ingress over time, not necessarily wood character. If an increase in sulfite leves helps to keep some of the acetic acid at bay that seems like it would be a good thing.

Rodenbach has the largest cellar of wood right? Unless NB does now. If both brands are using a lager yeast I would think it has to be for other reasons other than water production.

 

I don't think anyone purposefully wants oxygen ingress. It simply occurs due to the nature of the aging vessel. Saying that increased sulfite levels reduces acetic acid production in these scenarios is a stretch from saying minimal levels have anti-oxidant properties and prevent premature staling, though. Any citations on that hypothesis?

Possibly, but we'd need confirmation on the "brewing for sulfur" bit.

 

That's one of the things I love about a traditional pilsner, the ghost of sulfur.

@EvenMoreJesus if the . after quickly was a , then the we would be royal indeed.