I brewed a Belle-Saison and it's been in a carboy for 1 month now. Someone with a lot of experience told me he once bought a beer with Brett (Beer was "Orval") and droped the last 100ml into his fermenter and waited about 40days.

I never brewed a sour and I am more of a scientific approach normaly, but I am curious about this one.

What do you think? Will I get the result I am hoping for?

2 Answers 2


Brettanomyces comes in many forms, leading to many different flavour profiles. The main three you will come across commercially are:

  • B.Claussenii - Fruity with mild funk
  • B.Bruxellensis - Tasty Horse Blanket (this is Orval)
  • B.Lambicus - heavy funk with sour fruits

Depending on when you add the Brett to the fermentation will determine how soured your beer gets from the Brett. Brett operates in 2 modes, aerobic and anerobic and takes about 24-48 hours to transition between the 2. In the aerobic phase you will get higher levels of acetic production than in the anerobic phase [https://link.springer.com/article/10.1007/s00253-002-1197-z ]. You would be adding the B.Brux to the FV after primary fermentation is completed and therefore it would enter in an anerobic state and produce very little acetic acid.

If you wished it to make a sour you could put a porous bung(cork) in your carboy to allow oxygen exchange over the 40 days, which would allow the brett to metabolise the remaining complex sugars with some O2 present allowing for more acid production.

But, realistically for a real sour Sour, you either would want to do a kettle sour, or be adding the Brett at the start of fermentation ie with oxygen present, or adding it along with a mix of bacteria Lacto, Pedio, etc...

A great source of information about sours, brett, mixed fermentations is the Milk The Funk wiki:

And, above all don't fear the funk, just be ready to clean everything properly, and enjoy the funky flavours.

  • 1
    From what I read, orval uses a Bruxellensis yeast. For my primary fermentation I used a Bell-Saison yeast known to have high attenuation. My understanding from what you said and what i read tells me I won't get much "funkinest" from that manipulation since 100ml of bottled beer containing probably very little amount of yeast + no Oxygen + low sugars might not be enought
    – Boubou
    Commented Aug 28, 2019 at 16:55
  • you should get some good funkproduction, but probably very little acid production
    – Mr_road
    Commented Aug 29, 2019 at 12:01

Brett beers can be very interesting, and aren't necessarily sour unless the source also was sour. Brett usually gives more of a leather or "barnyard" character which can evolve with longer aging. Brett works very slowly so the 40-day guideline isn't far from the truth but you might need to wait even longer, many months possibly, to get much out of it. If you are interested, go ahead and give it a go. It shouldn't hurt anything, and might turn out awesome if you are patient and you think you will enjoy the Brett character.

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