Brett Off Flavors

[Wernerherzog]

I've been raising several different species up to 10 gallon pitches and am a bit concerned about some of the flavors I've tasted along the way to get the high cell-counts. I was curious if someone with more experience could advise me.

At the moment I have

ECY Naardenensis that smells and tastes a little vinegary. I haven't given an extreme amount of aeration to the starter, no stir plate for it. Could it still be acid from aerobic brett fermentation (cover was just foil, no airlock), or is it likely an acetobacter infection? The ECY Brux did the same thing for what it's worth, so I stopped growing that one up.

WLP Brux- has that harsh burnt rubber phenolic off flavor component. It's a pretty overpowering aroma. Will this continue on or do the flavor compounds change with time? I don't want a 10 gallon barrel of smoky rubber.

WLP Drie- Along with the beautiful typical tropical fruit aroma there is a distinct "dirty flower water" scent that is a bit off-putting. There is a slight acidity to this one, but not distinctly vinegary. This one sat on a stir plate for a week or so. Maybe just acid natural to the aerobic fermentation condition? Has anyone else experienced that dirty flower taste?

The WLP Brux cells were out of date (by a couple of months) when bought, I grew them up to 12 ounces, to 500 ml, to a half gallon, and am about to step up to a full gallon starter. I was hoping this would be enough to revitalize healthy remaining cells. Could the burnt rubber phenolic be caused by age?

Thankfully the WLP Clausenii and WLP Lambicus are tasting perfectly non offensive. Thoughts on the other 3? Thanks for the help!

 

[Oldsock]

Neither Brett nor Acetobacter can make acetic acid without oxygen, so the presence acetic acid isn't indicator for which microbe is present. It's probably fine.

I've only gotten burnt rubber in really hot fermentations, say 80F and above. It is possible you are particularly sensitive to phenols. From such a small amount it would have been smart to start with a smaller culture initially. How quickly did you see activity?

Often Brett strains will produce some weird flavors. Not sure exactly what flavor you are describing, but low levels of ethyl acetate can be fruity into solvent. It's derive from acetic and ethanol, so you wouldn't expect as much from the main batch.

 

[Wernerherzog]

Thanks for the words of comfort. Activity didn't take too long at all, a day. At this stage in development, they were all off and kicking within 2-4 hrs. Ferm temp has been ambient at 75 degrees. First starters were 12 oz, then 500 ml, then half gallon, now full gallon as of yesterday.

 

[trentm]

Thanks for the words of comfort. Activity didn't take too long at all, a day. At this stage in development, they were all off and kicking within 2-4 hrs. Ferm temp has been ambient at 75 degrees. First starters were 12 oz, then 500 ml, then half gallon, now full gallon as of yesterday.

Sorry I'm not qualified to help on the flavor issues. But I have a question regarding your stepped starter and a pitching rate comment.

Starter question first: When you start with the 12 oz starter do you pitch a full commercial pack?

Comment: You seem to be producing high cell count cultures. Recently, I bought a microscope and have been counting cells in my cultures and I use similar culture methods as you. With the main difference being I grow up from slants. This week I finished and counted a pure culture of Brettanomyes I had isolated from a bottle of Orval (this is the first time I have counted Brett). I was surprised to find my 1200 ml culture contained 710 million cells per ml (890 billion total)! That compares to an average of 275 million cells per ml for my Sacc cultures. If you have similar counts, your 1 gallon culture may contain >2.6 trillion cells!

Note; I have been professionally trained in using a hemocytometer and have a fair amount of experience.

 

[Wernerherzog]

trentm, I started with commercial packs for the WLP strains and for the ECY ones started with small amounts of a 5-gal pitch. The beer for these was made on the 26th, going to pull samples this Friday. We went ahead and pitched a full 1 gallon starter into each 10 gallon barrel, with one barrel being 15 gallons.

That's pretty insane if we used that much yeast.

I'll post flavor notes for anyone that's interested.

 

[trentm]

trentm, I started with commercial packs for the WLP strains and for the ECY ones started with small amounts of a 5-gal pitch. The beer for these was made on the 26th, going to pull samples this Friday. We went ahead and pitched a full 1 gallon starter into each 10 gallon barrel, with one barrel being 15 gallons.

That's pretty insane if we used that much yeast.

I'll post flavor notes for anyone that's interested.

Well for an all Brett fermentation large pitches are recommended so you may come out great with these brews. And making starters with a large inoculation rate you may get a lower total cell count. I have never done an all Brett so I'll be interested in your tasting notes.

For the Brett culture I mentioned above, I was doing a secondary Brett fermentation. I wanted to pitch 1 million cells per ml but I was leery about my cell count. I just couldn't believe there were so many compared to the counts of my Saccharomyces cultures. Since I had 2 ten gallon batches in 3 fermentors (2 - 5 gallon and 1 - 10 gallon), I pitched 1 million cells/ml to 1 of the 5 g, 1.5 million cells/ml to the other and 2 million cells/ml to the 10 g. All took off at the same time and now seem to be finishing about the same (4 weeks on Brett).