Mapping the sour beer microbiome

We actually extracted DNA from sour mashes as opposed to sour beer. We used a Zymo Research kit for DNA extraction (bead beating of pelleted microbes followed by numerous spin columns to separate and clean up the nucleic acids). One could do the same thing with beer sample though.

Thanks Indian Joe Brewing! We'll let you know when we start getting some results in!

Thanks Rick!

Also, I was able to give you some love on our kickstarter updates: https://www.kickstarter.com/projects/489252126/beerdecoded-the-1000-beer-genomes/posts/1605150

Luc, the BeerDeCoded project looks pretty cool. Are you guys going to publish anything in an academic journal? This is just the kind of stuff we'll be citing when we publish the results from this experiment.

Matthew, Jeff would be the better person to answer your questions, so keep an eye out for his response here soon.

Hey Matthew, I'm going to write up a more detailed description of our souring process under lab notes, but for right now I can tell you that we do indeed purge our incubation tank (40bbl modified kettle) with CO2 and we hold every batch at 113F +/- 2F

...or indeed with different batches of grain.

...and from different parts of the world.

Hi Andrew. I think making starter cultures from Weyer. acid malt is a good idea. I've used many different malts and seen many different results. We inoculate the entire batch of wort with the culture from the grain during the brew day OR we will pitch a bit of the previous beer's sour wort. So we can, and do want to assess "starter cultures" from our particular grain. We use Briess' Carapils as our inoculant. I've also used Weyer Cara Foam and even a few C-10s from different maltsters. We find the best results from the lowest kilned malts. A big factor for us is that we inoculate post-mash with additional malted grain. So the malt has to be basically "crystallized" or the wort will throw one terrible starch-haze! That's why CaraPils has been our grain of choice...although we're looking for alternatives, just haven't seen one that fits our criteria as well.

Hey Klara, if we do everything right in the brewery and hit our target conditions properly, we can achieve our "maximum potential titratable acidity" for the wort generally in well less than 24 hours. As the density of the wort goes up, so does the buffering capacity, and thus so does the wort's ability to resist pH change and allow the souring agents to create acidity until the pH drops below about 3.3. After it drops below a pH of about 3.3, very little additional acidity is created. So as a brewery, we try to get the level of acidity (TA) in the least amount of time. The beer we are tested is a pretty typical gravity wort (around 12P) and we find it hits the level of acidity we desire (around 0.65% as lactic acid) in about 18 hours. So to be honest, the data points will all actually probably be under 24 hours and the last one will be taken when the TA is about 0.65%.