Caffeine Transport in Single Cup
Coffee Packets
Eric Anderson
Alana Warner-Tuhy
Introduction
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Reason for Study
Experimental Parameters
Results
Conclusions
References
Justification for Study
• Warning on the back of coffee packet
• How much does brewing conditions affect the
final caffeine concentration?
Experimental Parameters
• Three different brewing methods
– No interference
– Dunk bag in water, as per directions
– Continuously stir
• Other than convective conditions, all other
parameters were constant
Purification and Extraction
Method 1 Results
Color and Caffeine Comparison
1
0.9
Nomalized Concentration
0.8
0.7
0.6
0.5
0.4
0.3
Color
0.2
0.1
Caffeine
0
0
1
2
3
4
5
Time (min)
6
7
8
9
10
Color Comparison
Color Dependence on Time
1.400
1.200
Absorbance
1.000
0.800
0.600
0.400
0.200
Still
Dunked for 15 sec at 1 min
Well Mixed
0.000
0
10
20
30
Time (min)
40
50
60
Caffeine Conc. Comparison
Caffeine Concentration
1
0.9
Caffeine Concentration (mg/mL)
0.8
0.7
0.6
Still
0.5
Dunked
0.4
Stirred
0.3
0.2
0.1
0
0
10
20
30
40
Time (min)
50
60
70
Final Caffeine Comparison
Method Time (min)
Final Concentration (mg/ml)
1
5
0.12
2
5
0.14
3
5
0.13
1
10
0.22
2
10
0.14
3
10
0.52
1
60
0.39
2
60
0.15
3
60
0.92
Results
5 Minutes
– Any method will work
10 Minutes
– Double the caffeine by leaving coffee undisturbed
– 4 times the caffeine by continuously stirring coffee
Conclusions
• The convective component greatly affects the
final caffeine concentration
• Color is not an adequate indicator of caffeine
concentration
References
• Spiro, M., Lam, P., Food Chemistry, 1995 , vol.
54, p393-396.