It is one of the most repeated claims in drinking folklore: bubbles get you drunk faster. Champagne hits harder. A vodka soda sneaks up on you in a way a vodka and water does not. It gets repeated so confidently that most people assume it is settled science.
It is not settled. But it is not nothing either — there is a real study that tested exactly this, and its design happens to map precisely onto the choice between a hard seltzer and a still canned cocktail. Here is what the evidence actually shows, where it is weak, and what it does and does not license you to conclude.
The study that measured it directly
In 2007, C. Roberts and S.P. Robinson published "Alcohol concentration and carbonation of drinks: the effect on blood alcohol levels" in the Journal of Forensic and Legal Medicine (PMID 17720590). Twenty-one subjects — 12 men and 9 women — each drank three different preparations on separate occasions:
- Neat vodka at 37.5% ABV
- Vodka with still water, diluted to 18.75% ABV
- Vodka with carbonated water, diluted to the same 18.75% ABV
Note the control that matters: the still and carbonated drinks contained identical amounts of alcohol at an identical strength. The only variable between them was the CO2.
What they found
The mean absorption rate on the carbonated drink was 4.39 ± 0.45 mg/100ml/min. On the still drink, it was 1.08 ± 0.36 mg/100ml/min. The difference was statistically significant (p = 0.006).
That is roughly a fourfold difference in how quickly alcohol entered the bloodstream, from the same dose of the same spirit, with the bubbles as the only distinguishing factor.
The finding almost nobody quotes
Buried in the same paper is a result that gets far less airtime and is arguably more interesting: 20 of 21 subjects absorbed the diluted alcohol faster than the neat vodka (p < 0.001). Not the other way around.
That runs against intuition. A stiffer drink feels stronger, so people assume it must hit faster. But very high-concentration alcohol appears to irritate the stomach lining and slow gastric emptying, effectively delaying its own absorption. Dilution to a sessionable strength — which is exactly what a 5% canned cocktail is — moved alcohol into the blood more quickly than a neat shot did.
Why bubbles would speed things up
Very little alcohol is absorbed through the stomach itself. The overwhelming majority crosses into the bloodstream through the small intestine, which has vastly more surface area. So the rate-limiting step in getting drunk is not really absorption — it is how fast your stomach hands the alcohol onward.
The proposed mechanism is that dissolved CO2 increases pressure and distension in the stomach, which accelerates gastric emptying and pushes the contents into the small intestine sooner. Same alcohol, delivered to the absorptive surface faster, so a steeper climb in blood alcohol.
That distension is also, incidentally, the same physical event people describe as bloating. The gas that has to go somewhere is the gas that was doing the pushing.
Now the honest part: this is not settled
A good brand should not quote one study as though it were a law of nature, so here are the caveats that matter:
- Twenty-one people is a small sample. Forensic absorption studies usually are — they are demanding to run — but it limits how far you can generalise.
- The effect was not universal. Even within this study, 14 of 21 subjects absorbed faster with the carbonated mixer. The other 7 showed no change or absorbed more slowly. Whatever is happening, it does not happen to everyone.
- The wider literature disagrees with itself. Other work has found carbonation makes no significant difference, and some suggests it may actually delay gastric emptying. Studies on alcohol and gastric motility are notoriously inconsistent, because beverage composition, food in the stomach, sex, body composition and individual physiology all interfere.
- Absorption rate is not the same as getting drunk. A faster climb to peak blood alcohol is not the same thing as a higher peak, and neither is a straightforward measure of impairment.
The intellectually honest summary: there is credible, directly-measured evidence that carbonation can accelerate alcohol absorption in many people, the mechanism is plausible, and the effect is not consistent enough to treat as a rule.
What this does not mean
It does not mean a still drink is a safe drink, and we are not going to pretend otherwise. A can of Aura contains the same alcohol whether it fizzes or not. Absorption speed changes the shape of the curve, not the dose. If you drink four cans, you have drunk four cans.
What it may change is how predictable the experience is. A slower, flatter climb is easier to read as it happens. The complaint behind "it sneaked up on me" is usually a mismatch between how much you had consumed and how much you felt — and a steeper absorption curve widens that gap.
Doing the Canadian arithmetic
Since absorption speed is the interesting part but dose is the part that counts, it is worth knowing what you are actually holding. Under Canada's Guidance on Alcohol and Health, published by the Canadian Centre on Substance Use and Addiction in 2023, a standard drink is 17.05 mL (13.45 g) of pure alcohol.
A 355mL can at 5% ABV contains 17.75 mL of pure alcohol. So one can is almost exactly one standard drink — about 1.04, to be precise. That is a genuinely useful property: no mental conversion, no guessing at a bartender's pour. You are counting in the same units the guidance is written in.
That guidance, which replaced Canada's 2011 Low-Risk Drinking Guidelines, frames alcohol as a continuum of risk rather than a limit to stay under: 2 standard drinks or fewer per week is described as low risk, 3–6 as moderate, and 7 or more as increasingly high risk. Worth knowing what the current Canadian position actually is, whatever you decide to do with it.
Where Aura sits in this
Aura is a still vodka water: premium distilled vodka blended with alkaline water, no added sugar, no artificial sweeteners, gluten-free, and zero carbonation. We did not remove the bubbles because of a 2007 forensic-medicine paper — we removed them because carbonation makes a meaningful share of drinkers uncomfortable, and because CO2 is a blunt flavour tool that masks whatever it is poured over.
The absorption research is a footnote to that decision rather than the reason for it, and we would rather present it with its caveats attached than dress up one small study as proof of something. Read more about why Aura is made without carbonation, browse our vodka water cocktails, or find where to buy across British Columbia, Alberta and Ontario.
Sources
- Roberts C, Robinson SP. "Alcohol concentration and carbonation of drinks: the effect on blood alcohol levels." Journal of Forensic and Legal Medicine, 2007;14(7):398–405. doi:10.1016/j.jflm.2006.12.010. PMID 17720590
- Canadian Centre on Substance Use and Addiction. Canada's Guidance on Alcohol and Health, 2023.
This article summarises published research for general interest and is not medical advice. Aura products are for adults of legal drinking age. Please enjoy responsibly, and never drive after drinking.