Brett and Sour

[brewinhard]

I'm considering lacto souring a gallon of wort on the side using the lacto living on grain and then adding back to the batch when it is ready. This is definitely an intricate multi-step process that needs to be well thought out and planned if you don't want to toss the dice and take a chance. I'm of half a mind to let local microflora have their way but the other half of me says "hell no!" I like the idea of it being local, unique, and artisanal. I don't like leaving it up to chance. You know Vinnie doesn't leave it to chance. He knows what he's doing and takes it through the process. Maybe I'll just do two beers. Problem solved.

If you do decide to make a lacto starter using grain I highly recommend trying to minimize any oxygen pickup and if possible purge your container with CO2 to prevent any nasty off-flavors associated with this process (butyric, enteric, etc). A bad sour mash can smell like putrid, rancid, vomit, cheese, and crap. You definitely don't want to add that to your beer.

[Cody]

If you do decide to make a lacto starter using grain I highly recommend trying to minimize any oxygen pickup and if possible purge your container with CO2 to prevent any nasty off-flavors associated with this process (butyric, enteric, etc). A bad sour mash can smell like putrid, rancid, vomit, cheese, and crap. You definitely don't want to add that to your beer.

I wonder how much of this is from other organisms living on the grain. If you were to do a two- or three-step starter, would this solve the problem?

[brewinhard]

It might, as the lowered pH would kill off any of the other microorganisms causing the rancid flavors. But keeping oxygen at bay is the best way to minimize this risk. In all reality, by the time you buy a $9 pack of lactobacillus and make one starter with it, you might have equaled out all the work going into making 2-3 starters from the grain. Then you are guaranteed to just have only the bacteria you desire.