Claim: Swallowing active dry yeast before drinking alcohol will prevent you from getting drunk.
Examples:[Collected via e-mail, April 2014]
"How to drink without getting drunk" by drinking yeast? Will this work?
Origins: In April 2014, Esquire magazine published an interview with billionaire Jim Koch, the co-founder and chairman of the Boston Beer Company. In that interview, Koch divulged his secret for how to "drink beer all night long and never get drunk" — the secret being to swallow one teaspoon of active dry yeast per beer prior to imbibing:
"You wanna know my secret? How I can drink beer all night long and never get drunk?"
In fact, I had always wondered that. Though this was the first time I'd ever formally met Koch, I'd "met" him in the past at a few beer festivals. Those sorts of events are always kind of Bacchanalian shit shows, with people imbibing dozens of beer samples in a short period and soon stumbling around large convention halls drunk of their asses. Brewers included. But not Koch, who I’d long noticed was always lucid, always able to hold court, and hold his own with those much younger than him. This billionaire brewing raconteur was doing likewise with me at 4 PM on a Thursday afternoon despite the fact we were both now several beers deep. So what was the secret?
"Active yeast. Like you get at the grocery store."
Koch told me that for years he has swallowed your standard Fleischmann's dry yeast before he drinks, stirring the white powdery substance in with some yogurt to make it more palatable.
"One teaspoon per beer, right before you start drinking."
The claimed science behind this secret is that yeast produces a group of enzymes known as alcohol dehydrogenases (ADHs) that break down alcohol molecules into their constituents (carbon, hydrogen, and oxygen) just as your body does when alcohol is metabolized by your liver. So by consuming ADH-producing yeast prior to drinking, you will supposedly create an environment in your stomach that breaks down much of the alcohol you take in before it reaches your blood and brain, thereby preventing you from getting (as) drunk as you normally might.
But will Jim Koch's trick really work, or was he having one over on his audience? As Business Insider noted, even if the suggested method did work, it could have some pitfalls that might make the cost not worth the benefit:
Toxic byproducts are created when the ADHs break down the alcohol. This is what causes a hangover the morning after a night of heavy drinking. Since the yeasts add extra ADH into the body, thus creating more toxic byproducts, we are guessing this little trick could make your hangover worse, even if you managed to stay sober.
There's also a risk of getting too much yeast into your system. Since these organisms naturally produce alcohol, overdoing it on the yogurt-yeast concoction could have the opposite effect and make you drunker. In one case, a home brewer turned himself into an alcohol-creating machine whenever he ate too much sugar.
As well, a number of online critics have expressed skepticism about Koch's suggestion. One frequently mentioned doubt is that the effectiveness of a teaspoon of swallowed yeast would largely be neutralized by the acidic environment of our stomachs, as noted by one commentator in a skeptics forum:
Inside the stomach the pH is around 1-2, the activity of enzymes is typically strongly dependent on the pH. Outside of their optimal pH range enzymes generally work much slower or not at all.
Yeast ADH has a pH optimum in the neutral to alkaline range, at low pH values it is not active at all. The following two papers looked at the effect of pH on ADH and both observed that ADH was unstable at low pH values
From "The Role of Zinc in Alcohol Dehydrogenase: V. THE EFFECT OF METAL-BINDING AGENTS ON THE STRUCTURE OF THE YEAST ALCOHOL DEHYDROGENASE MOLECULE":
At acid pH, both activity and zinc of the enzyme are lost also (18, 19), but the effect of H+ ions on the structure of the enzyme differs markedly from that here described for chelating agents. Yeast alcohol dehydrogenase, 3.3 x 1O-5 M, when dialyzed for 24 hours in 0.1 M sodium acetate, pH 4.0, 0°, becomes polydispersed and precipitates on increasing the temperature by only 4°. Apparently, H+ ions critically affect sensitive groups of this enzyme in addition to those involved in activity and zinc binding.
From "Effect of pH on the Liver Alcohol Dehydrogenase Reaction":
We are unable to study the rate of hydride transfer at more acidic pH values because our enzyme preparation undergoes rapid loss of activity below pH 5.9
So the proposed mechanism of the higher alcohol tolerance is highly implausible. There could be an effect of eating yeast separate from ADH, or yeast could have isoforms that also work at lower pH. But as the only evidence in favor seems to be anecdotal I would doubt that eating yeast as a significant effect.
The ADH is not unlikely to be exposed to the stomach pH in yeast, so this only matters to the extent that yeast's structural integrity is compromised. Since yeast generally tolerate acidity quite well (easily down to a pH of 4 for some yeasts) there is a reasonable chance that the yeast could thrive in the upper ranges of stomach pH. An example of this can be found here where a man had a persistent infection in his stomach that was actually fermenting to produce alcohol.
The Esquire article mentioned Joseph Owades, a biochemist who specialized in the study of fermentation and alcohol metabolism and patented a product called Prequel, an active dry yeast-based capsule intended to limit drunkenness. Although Owades' product was never marketed (purportedly because no company wanted to deal with its potential liability issues), and the issuance of a patent is no guarantee that an invention works as claimed, the background research included with his patent submission suggests that his method might indeed be effective for its intended purpose:
Eighty-eight milliliters of 80 proof vodka, diluted with 80 ml. of water are consumed by a young, 160 pound adult woman, within 5 minutes. The alcohol content in the breath, directly proportional to the blood alcohol level, is measured periodically until the level falls below 0.002%.
The experiment is repeated, with the same woman, but this time, 2.5 g. of active dry bakers yeast is ingested followed by 88 ml. of 80 proof vodka diluted with 80 ml of water. The alcohol content in the breath is measured periodically.
The results for both tests are shown in FIG. 1 and show the decrease in blood alcohol level caused by the yeast. The decrease, as measured by the areas under the curves in blood alcohol level - min. was 29%.
The same tests, without and with the ingestion of 2.5 g. of active dry bakers yeast were done. This time the tests were run with a young, 155 pound adult man. The results for both tests are shown in FIG. 2. The decrease in blood alcohol level when the yeast was taken is clearly shown, and quantitatively demonstrated by the reduction in blood alcohol level-min. of 23% in the areas under the curves.
A mature 170 pound adult man consumed 268 ml. of chardonnay wine, 13% alcohol by volume in 11 minutes. His blood alcohol level was measured periodically. The test was repeated, by the same man, but this time 2.5 g. of active dry vintners yeast was ingested just before the wine was consumed. The blood alcohol level was measured periodically.
The results are shown in FIG. 3. The ingestion of the yeast lowered the peak level and decreased the area under the curve, in blood alcohol level-min. by 36%.
A mature, 170 pound woman performed the same tests as in Example III.
The results are plotted in FIG. 4. The areas under the curve, in blood alcohol level-min., decreased by 21% when the yeast was taken just before the wine was consumed.
Seven hundred and ten ml. (24 oz.) of a standard American beer (5% alcohol by volume) was consumed by a mature, 150 pound adult woman in 13 minutes, and then the blood alcohol level was measured periodically.
The same woman ate 5.0 g. of active dry bakers yeast and then drank the same volume of the same beer. The blood alcohol was measured periodically.
The results are shown in FIG. 5. The yeast reduced the area under the curve, in blood alcohol level-min., by 26%.
Twenty-four ounces of a standard American beer, the same as in Example V, was consumed by a mature, 140 pound adult man in 8 minutes. His blood alcohol level was measured periodically.
The same amount of the same beer was consumed by the same man, except 2.5 g. of active dry bakers yeast was taken at the start of the beer drinking, which was finished in 14 minutes. Blood alcohol levels were measured periodically.
The results of both tests are shown in FIG. 6. The area under the curve, in blood alcohol level-min., was reduced by 30% by the yeast.
Twenty-four ounces of a light beer, alcohol content 4.2% by volume, was consumed by a mature, 150 pound adult woman, after 3.0 g. of active dry brewers yeast was ingested, all in 15 min. The blood alcohol level was measured periodically.
The same amount of the same beer was consumed by the same woman, but without any yeast.
The results of both tests, are shown in FIG. 7. The area under the curve, in blood alcohol level-min. was reduced by 38% by the yeast.
A mature, 155 pound adult man consumed 24 oz. of the same beer as in Example VII, right with the ingestion of 1.5 g. of active dry bakers yeast. His blood alcohol level was measured periodically.
The above test was repeated, but without ingestion of any yeast.
The results are shown in FIG. 8. The area under the curve, in blood alcohol level-min., was reduced by 38% when yeast was taken.
Anecdotally, Koch's Esquire interviewer, Aaron Goldfarb, tried out the former's "secret" and reported that he felt it had worked:
Of course, I had to honor my longtime hero Koch, and a new beer hero I'd just learned about in Owades, and try this trick myself. So the next day I grabbed a six-pack of beer and a packet of Fleischmann's and went to work. The older I get, the more of a lightweight I surely become, but after shoveling down six teaspoons and tilting back six bottles I felt nothing more than a little buzzed. Koch told me he keeps a breathalyzer around at all times just to assure he's never too drunk. He never is. And, though I had no tangible "proof," besides the fact I was still awake, I was pretty sure I wasn't all that drunk either.
For now, a definitive answer awaits empirical evidence gathered through properly controlled studies.