Attempting 13% ABV straight, unblended sour

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spenghali

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This beer's original plan was to be a big brett strong ale with fruit, but I called an audible a few weeks before and decided to attempt a strong sour. I threw everything I had at it, a few different strains of sacch, all the brett strains, 20+ commercial dregs starter, a fresh pack of pedio, and a lot of time. I am mostly relying on there being some alcohol tolerant bacteria in the commercial dregs somewhere. OG: 1.111, down to 1.020 two weeks later, i'm hoping to hit 1.010 at least, wish me luck, full details on blog.
 
I had thought of pitching the pedio solo before everything else, but was worried about inviting other infections into such a high gravity, low IBU environment.
 
I have a three month old imperial flanders red(OG 1.111) that I started with just lacto for three days then I added Roeselare and dregs. When I get home from work tonight I will take a sample and gravity reading.
 
I wonder how the lacto handled that. I'm wondering what the OG ceiling is for some of the bacteria. Even a high enough sugar concentration can make a product shelf stable, similar to alcohol.
 
It's a function of osmotic pressure. This is why packaged food is often very sugar, very salty, or very dry. The bacteria need water and if the ionic concentration of anything is greater than they can balance it causes the cells to either shrivel up or burst. If I can remember it's called water activity. It's a very big deal with fermented and dry cured sausages.

In most cases lactic acid bacteria have an alcohol tolerance around 8% with some probably having wiggle room. They can probably be slowly exposed to higher and higher concentrations giving them increased tolerance but that might take a few months.
 
Water activity is the amount of water present that is available to microorganisms. So I guess what you said is correct, if the ion concentration of anything is high enough, the water activity is going to be very low and the bacteria will not survive.

I'm really curious what the threshold would be for lacto or pedio versus sacch or brett.
 
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