Understanding Brettanomyces

I agree with most of this. A few things:

Originally posted by HornyDevil
So . . . what does this all mean in the construction of Brett beers? Here’s what I would recommend for both 100% Brett fermentations and Sacch + Brett fermentations. Other mixed microbe fermentations, like those that include lactic acid bacteria, I’ll leave for later.

1) Use a simple grist with barley and wheat or oats to increase your mouthfeel via beta-glucans, as most strains of Brett are hyper-attenuative and tend to leave beers tasting thin.

I’m struggling to find papers on this right now, but I believe brettanomyces can ferment the beta-glucans in oats, using the same glucanase enzymes it uses to break up the exo-poly-saccharides in ropy beer (beta-glucans are also exo-poly-saccharides). So it’s not clear this works.

Do a ferulic acid rest. More ferulic acid = more Brett character, especially in beers that you use Sacch. first. In those beers Brett will take the increased amount of 4 vinyl guaiacol (as compared to a 100% Brett beer) and reduce it into 4 ethyl guaiacol which has a smoky, spicy, and clove character.

You have to like a lot of 4EG to want to maximise it. Not everyone necessarily wants lots of that sort of character. So, I agree, if that’s the brettanomyces character you want, but I don’t think it’s as simple as ’If you like brettanomyces character, maximise 4VG production’.

If you’re using a Sacch strain, use a highly clove forward strain and/or one that produces a decent amount of glycerol. The former is because those strains produce a lot of 4VG. The second because of the hyper-attenuative nature of many Brett species.

Glycerol is also a polysaccaride. I don’t know if any brettanomyces strains can ferment it, but it might be that some can, and some other micro-organisms definitely can (most acetobacter, for example). I doubt this is any issue for anything beyond spontaneous fermentation and things (like Flemish sour ale) with some acetobacter activity, but I’d like to know more about it and if anyone thinks it’s likely any brettanomyces strains can ferment this.

Expect a longer fermentation, especially for 100% Brett beers. Most normal gravity beers will reach a stable terminal gravity in the 4 - 6 week range, but higher gravity ones will probably take a little longer. I tend to give all of mine at least 8 weeks, just to make sure.

This will depend a little bit on the strains you’re using and how fermentable you make your wort. I tend to make my wort very fermentable, and so, unless it’s a higher gravity beer, I hit my finishing gravity pretty fast. Often less than a week, normally less than two weeks.

Cheers again for starting the thread. Interested to hear what others have to say.

Originally posted by GarethYoung
I agree with most of this. A few things

Agreed on all that you’ve said. Difficult subject to say definitive things in a concise manner due to the variability between strains and the lack of research on each and every subject, that’s why I mentioned generalization. I think it’s a good jumping off point, though. Gotta start somewhere, ehh?