pH of Coca Cola

Kristina Rudnitski

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Jun 30, 1998, 3:00:00 AM6/30/98

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Hi,

I've been searching the web to find out what exactly is the pH of Coca
Cola and have only found the pKa of phosphoric acid. Does anyone know
what the overall pH is, factoring in the corbonic acid? It's just been
on my mind lately.

Thanks,

Kristina

Jan Marik

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Jun 30, 1998, 3:00:00 AM6/30/98

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Hi,
I measured it and it has pH = 2,8.
Enjoy it.

Jan

Mike D.Wright

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Jun 30, 1998, 3:00:00 AM6/30/98

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In article <3598C6...@htw.uni-sb.de>, Kristina Rudnitski <gast-
0...@htw.uni-sb.de> writes

>Hi,
>
>I've been searching the web to find out what exactly is the pH of Coca
>Cola and have only found the pKa of phosphoric acid. Does anyone know
>what the overall pH is, factoring in the corbonic acid? It's just been
>on my mind lately.
>
>Thanks,
>
>Kristina

Did you actually search Usenet? The pH of coca cola is in paragraph
31.19 of the sci.chem FAQ (part 7 if your newsreader can see the FAQ.)

Mike Wright, HSL, Broad Lane Sheffield S3 7HQ, UK
Tel +44 114 2892000
Fax +44 114 2892362

Dr. Henry

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Jun 30, 1998, 3:00:00 AM6/30/98

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I believe (based on my memory of measurements) Coke and Pepsi run 4-4.5. Dr.Pepper and Mt Dew run
3.5-4. On average they are all around 4. It may also vary a little by batch and source
(can,bottle,fountain, etc).

--

Dr. Henry Boyter, Jr. Ph.D. Chemist

The opinions of Dr. Boyter are provided for informational purposes only and should not be used as
advice. No warranty or expression of professionalism is implied.
Kristina Rudnitski wrote in message <3598C6...@htw.uni-sb.de>...

Bruce Hamilton

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Jul 1, 1998, 3:00:00 AM7/1/98

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In article <3598C6...@htw.uni-sb.de>
Kristina Rudnitski <gas...@htw.uni-sb.de> writes:

>I've been searching the web to find out what exactly is the pH of Coca
>Cola and have only found the pKa of phosphoric acid. Does anyone know
>what the overall pH is, factoring in the corbonic acid? It's just been
>on my mind lately.

You didn't search very hard. The answer is in the sci.chem FAQ which is
also on the WWW.

[ Begin Extract ]

31.19 What is the pH of Coca-cola?.

Phosphoric acid is an approved food-grade acid that is added to Coca-cola
to provide some of the taste. When CO2 is added to "carbonate" aqueous
solutions, carbonic acid is formed. A tin of coca-cola was cooled in a
refrigerator to 7C and the pH of the sample measured over time. The pH
electrode was not temperature-compensated, so a correction was applied.

Time pH pH
(when opened) (corrected)
Initial 2.75 @ 7C 2.6
30 seconds 2.78 @ 7C 2.6
60 seconds 2.80 @ 7C 2.6
2 minutes 2.82 @ 7C 2.7
4 minutes 2.80 @ 7C 2.6

A sample was degassed in an ultrasonic bath for several minutes and the
pH measured, and compared to a control sample maintained at the same
temperature and time profile.
pH
Degassed pH 2.52 @ 21c
RT sample 2.50 @ 20C

So the conclusion is that the pH of Coca-Cola is approximately 2.5 - 2.7.
Not surprisingly, the relatively weak carbonic acid from the dissolved CO2
did not significantly affect the pH of the beverage. The aluminium beverage
containers are lined with a thin polymer or lacquer coating to prevent the
aluminium metal dissolving into the beverage.

Note that the differing flotation characteristics of cans of the normal
versions of carbonated beverages like Coca-Cola ( they may sink ), and
the diet versions ( they may float ), has nothing to do with the amount
of CO2 present. It is due to the increase in solution density from the
few percent of sugar added to the normal version, while the diet version
has only a few hundred ppm of an artificial sweetener that is much sweeter
than sugar.

[ End extract ]

Bruce Hamilton