Why does the first mouthful of Coke taste so much better than the rest?

Factual Questions
#1

Inspired by [url=http://boards.straightdope.com/sdmb/showthread.php?t=265397]this thread, I’ve often wondered why the first mouthful of Coke tastes so different from – and so much better than – subsequent mouthfuls. It can’t be due to the drink going flat or getting warm, since the effect is noticeable even after only a few seconds of opening the can (I hate icy-cold drinks anyway). It doesn’t seem so noticeable, however, if you drink through a straw.

Anyone else find this? Any ideas why? Is my tongue being desensitised by the bubbles, or something? I always find that by the time I’m halfway through a can, I’ve gone right off it. This effect happens chiefly with cola, but also with other soft drinks. It doesn’t happen with beer, though…

#2

The impact of the sugar (or fructose) on your tongue is dulled over time. Those drinks that have high levels of sugars in them act on your tongue the same way your skin might act when exposed to a change in temperature. Walk into an air-conditioned building from a hot and humid exterior, and you notice it pretty quickly. After a few minutes, though, the effect is lessened and must be noteced on a concious level.

#3

…Or it may be that whatever makes the first swallow taste good separates and floats to the top of the container. Try shaking it up before you open it and see if the results are the same. :smiley: In the name of science of course.

#4

Colas have a pH around 3. This is outside the range of maximum sensitivity for your tastebuds… so you fry them with the phosphoric acid and it takes them a while to recover.

#5

But I find the same thing happens with Diet Coke - no sugar there.

I guess 1010011010 has the answer.

#6

In addition to decreased sensitivity due to sugar and acid content, there’s the caffeine factor. If you drink caffeinated soda’s every day, you may have developed a physical dependance on the caffeine, which that first mouthful relieves.

More simlpy, you may be a caffeine addict getting your fix.

#7

Would you like to try that link again?

#8

A possible minor factor: the aftertaste of the corn syrup kicking in. Next Passover, try picking up some limited-production, kosher, cane sugar-sweetened Coke in two-litre and 20-oz. bottles (this spring, they were differentiated with yellow bottlecaps instead of the red). Big difference.

Or if you travel overseas, to a country with either a native sugar-cane industry or no scruples with respect to trading with Fidel’s Cuba, try their version of Coke…