Acid, not bubbles, responsible for distinctive 'bite' of carbonated beverages, researchers reveal

Aug 21, 2013
Acid, not bubbles, responsible for distinctive 'bite' of carbonated beverages, researchers reveal

New research from the Monell Center reveals that bubbles are not necessary to experience the unique 'bite' of carbonated beverages. Bubbles do, however, enhance carbonation's bite through the light feel of the bubbles picked up by our sense of touch.

The refreshing bite of carbonation is an integral part of beverages consumed around the globe. Carbonated beverages are produced when carbon dioxide is dissolved in a liquid, typically under high pressure. This can happen naturally in certain spring waters or in fermented beverages like beer. Carbon dioxide also can be added to beverages through production processes.

In either case, when pressure is reduced by opening a bottle or can of a carbonated beverage, some of the carbon dioxide is released from the solution in the form of . After a sip, enzymes in the mouth convert the remaining free carbon dioxide into carbonic acid. The acid then activates sensory nerve endings, which signal the mild irritation that we refer to as 'bite.'

In the study, published in the public access journal PLOS ONE, the Monell researchers examined the role that bubbles play in carbonation bite. In the first experiment, they took advantage of the fact that bubbles cannot form when atmospheric pressure is raised above a certain level.

Twelve healthy adults were comfortably seated in a and asked to rate the bite intensity of several concentrations of carbonated water. The ratings were collected once while under normal (with bubbles) and a second time at higher pressure (no bubbles), equivalent to diving to a depth of 33 feet in .

There was no difference in the bite reported in the two conditions, even though bubbles are physically unable to form at the higher pressure.

"Because the subjects experienced the same bite when bubbles weren't present, the findings clearly told us that carbonation bite is an acidic chemical rather than a purely physical, tactile one," said study author Bruce Byant, PhD, a sensory biologist at Monell.

Although bubbles aren't necessary for bite, they still could be contributing to the overall sensation of carbonation. Thus, a second experiment was designed to address this possibility.

In this experiment, 11 adults rated the intensity of bite in a laboratory setting. The ratings were made for carbonated water under normal conditions and again when additional air bubbles were added to the liquid.

The researchers were surprised to find that air bubbles enhanced the bite of the carbonated bubbles, presumably by stimulating the sense of touch.

"We thought the touch of the bubbles would suppress the painful aspects of carbonation, much as itching a mosquito bite or rubbing a sore muscle does," said Bryant.

Together, the studies reveal that bubbles are not directly responsible for the bite of carbonation. However, by stimulating the sense of touch inside the mouth, bubbles do enhance the bite sensation beyond the chemical irritation caused by carbonic acid.

"Pain from some cancers also depends on acid formation in tissue," noted study lead author Paul M. Wise, PhD, a sensory psychologist at Monell. "Because the bite from carbonation can be considered to be a mild type of pain, the fact that pain intensity can be enhanced via the may have implications for understanding these types of cancer pain."

Future experiments will continue to explore the interactions between chemical and mechanical stimuli.

Explore further: High-quality drug testing helps protect the integrity of California horse racing

More information: dx.plos.org/10.1371/journal.pone.0071488

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User comments : 15

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barakn
2.7 / 5 (3) Aug 21, 2013
Considering that nitrogen-infused beer doesn't have the same bite, some of us have known this for decades.
Kron
1.2 / 5 (17) Aug 21, 2013
Carbonic acid. H2O plus CO2 produces H2CO3.

The main way carbon dioxide (greenhouse gas) gets washed out of the atmosphere.

This little tid-bit is usually "forgotten" by Climate Scientist preaching anthropogenic global warming.
barakn
4 / 5 (4) Aug 21, 2013
Since the concentration of CO2 in the atmosphere has been directly monitored for decades and has been steadily increasing, clearly carbonic acid production is insufficient to handle the extra CO2 produced by humans. And the notion that it is ignored by climate scientists is laughably ignorant - it's a component of every carbon budget diagram: http://nimbus.elt...img7.gif
Kron
1.2 / 5 (19) Aug 21, 2013
There has been no significant increase in global temperatures so obviously enough CO2 gas is being removed. Not sure if you've noticed, but following intense heat waves are intense storms. The hotter it gets, the taller the clouds get, the more rain falls. After the storm there is a noticeable temperature drop. The higher we drive global temperature, the stronger the Earths response. This is natural regulation.

There has been no significant global temp change, therefore there has been no need for an increase in CO2 removal.
Kron
1.2 / 5 (18) Aug 21, 2013
Or perhaps CO2 does not play as much of a role in heat retention as it is professed to. It seems that the atmospheric concentration of CO2 is increasing and yet, temperatures are failing to.
Gmr
5 / 5 (4) Aug 21, 2013
Or perhaps CO2 does not play as much of a role in heat retention as it is professed to. It seems that the atmospheric concentration of CO2 is increasing and yet, temperatures are failing to.

Or maybe little pixies will magically supress carbon. Just so you understand, data is generally researched, and not made up out of whole cloth on the spot in a comment section.
Kron
1 / 5 (16) Aug 21, 2013
Global average temperature hasn't risen by a single degree Celsius since industrialization. Maybe the little magical pixies are blowing cold air and mitigating the effect that carbon dioxide is having on global temperatures.
retrosurf
4.4 / 5 (5) Aug 21, 2013
Brewers have know this for a long time. I'll toss another PhD worth observation: in force carbonation, there is a definite time lag between the time that you suffuse the cold beer with CO2, and the time that the CO2 is converted to carbonic acid; on the order of hours to maybe as long as a day. Before then, you get a gassy beer that sheds is carbonation readily. Reaction rates, equilibrium constants, mumble, mumble.

Hey, could you climate jerks give it a rest?
We're talking about carbonation here, not about climate change.

Gmr
3.7 / 5 (3) Aug 22, 2013
Global average temperature hasn't risen by a single degree Celsius since industrialization. Maybe the little magical pixies are blowing cold air and mitigating the effect that carbon dioxide is having on global temperatures.


^ Another Kron Job.

That is a fascinating tie-in to pain research - lactic acid burn is common if you've worked out or exercised to muscle failure. There are other research efforts into some pain sensors trying to block pain receptors and reaction at the level of the sensory neuron rather than with opiates in the brain. It would be interesting to try the pain mitigation using this as a measure instead of the hot near burning used currently.
Humpty
1 / 5 (7) Aug 22, 2013
Any rotten perfectionistic alcoholic researcher who is researching the perfect brew, and is somewhat pissed out of their mind and lives in a cold climate or is in a stinking hot one, and has access to beer etc., can tell you this, about a beautiful cold foaming head on the beer and that consumate refreshing mix of natural carbonation and bitterness from the assorted ingredients. We are talking about REAL beer here, not the factory made salty water weasles piss.
alfie_null
4 / 5 (3) Aug 22, 2013
Global average temperature hasn't risen by a single degree Celsius since industrialization. Maybe the little magical pixies are blowing cold air and mitigating the effect that carbon dioxide is having on global temperatures.


1. We have only been measuring it since the start of industrialization. Implying otherwise is being deceptive.

2. Implying that the temperature hasn't been rising is also misleading. And if I were to be pedantic, it has indeed risen by 1 degree, rounded. Again, you are being deceptive.

In your strong desire to promote some view, you are willing to abandon truth. Perhaps even to yourself.
rockwolf1000
5 / 5 (3) Aug 22, 2013
Carbonic acid. H2O plus CO2 produces H2CO3.

The main way carbon dioxide (greenhouse gas) gets washed out of the atmosphere.

This little tid-bit is usually "forgotten" by Climate Scientist preaching anthropogenic global warming.


If that were completely true then the CO2 in any carbonated beverage would mix with the water present in the beverage and form H2CO3 before it even got into your mouth and the bubbles would simply disappear. Obviously this doesn't happen in my beer nor does it happen in the atmosphere.
Hey that rhymes.
rockwolf1000
5 / 5 (3) Aug 22, 2013
It is also obvious that the "bite" is due to the acid and not the bubbles to anyone who has had a drink of Coke that has been kept in a hot car. The bubbles are the same. The bite is much stronger due to the temperature of the beverage and hence the acid.
Q-Star
5 / 5 (1) Aug 22, 2013
The people, who are stupid enough for not being able to recognize, they're off-topic with their ideas here only barely can be right even with their truth.


Boyo Zephyr, that is one that I sure do agree with (it's a shame that we would disagree about the subject and object in that true thing ya say.)
wwqq
5 / 5 (2) Aug 22, 2013
This little tid-bit is usually "forgotten" by Climate Scientist preaching anthropogenic global warming.


That's the cause of ocean acidification.

There is an equilibrium between the oceans and the atmosphere; the oceans can only suck about half of the CO2 we add to the atmosphere back out(most of which already occured)

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