Assuming the story and case study are true, and the guy had yeast in his stomach fermenting food he was eating, how much alcohol could be produced?
The guy had a blood alcohol level that would usually lead to hospitalization.
The Wikipedia article on auto-brewery syndrome contains a reference to this 2000 publication, which claims some “abnormally” high BACs, but no reliably reported instances of deleteriously high BACs.
The recent Texas case, if true, would be quite the outlier.
Minor correction: “gut”, not “stomach”. I would assume that the strongly acidic environment of the stomach would kill yeast pretty quickly, so the fermentation would probably be occuring in the small intestine. Which is also where the resultant alcohol would be absorbed.
Judging from the Wikipedia table, .4% BAC is on the edge of the “respiratory failure, coma” level. So, yeah, pretty messed up for not having a drop pass any orifice.
But how does the timing work out? Doesn’t food usually pass through the intestines in a day or so at most? I wouldn’t expect any brew to be very strong after only a day. Unless another aspect of this condition is a slowing of the digestive process?
To get the best flavor, you brew with yeast at lower temperatures, something like 70 for most ales, as low as upper 40s for lagers.
It will ferment much faster at higher temps and won’t be killed off until you get to temps above 100, closer to 110 or 120.
If you give large colonies of yeast a sugary medium (your body breaks down carbs into sugar) to grow in with their waste products being absorbed straight into your blood (alcohol), it’s not surprising you get rapid fermentation.
Durring the fermentation process the brew gives off a steady flow of co2. In the warm envirement of the body I imagine fermentation would be very rapid and the guy would have to have very large amounts of gas or bloating. I find it hard to believe that the intestines could hold enough product to produce enough alcohol to get drunk on. The stomach would have digested most of the carbs and sugars before it entered the intestines.
Carbohydrates are primarily digested in the small intestine. Carbohydrate - Wikipedia
Besides sugars most definitely are in the small intestines and that’s all brewer’s yeast would want.