International Conference on Emerging Trends in Engineering and Technology (ICETET'2013) Dec. 7-8, 2013 Patong Beach, Phuket (Thailand)
The Investigation of the Caffeine Contents in
the Classic, Gold and Turkish Coffees
M. B. Piskin, F. Demir, A. S. Kipcak, O. Dere Ozdemir, E. Moroydor Derun

coffee across the globe, at present Brazil is the largest
producer and exporter of coffee in the world [4].
Botanically coffee plant belongs to the genus Coffea of the
Rubiaceae family with more than 70 species [5]. Coffee is the
core of the fruit of a tree [1]. The coffee plant has a white
blossom that smells like jasmine and a red, cherry-like fruit
which is shown in Fig.1 [6].
Abstract— Coffee is a widely consumed beverage that
contains many components. Caffeine (3,7-dihydro-1,3,7trimethyl-1H-purine-2,6 dione), a purine alkaloid, is a key
component in coffee. In this study caffeine contents of three
types of coffees are determined by using two different
methods. Selected coffees are separated as water soluble
(classic and gold) and water insoluble such as Turkish coffee.
In water soluble method coffees are brewed and separated two
phases by adding chloroform. After filtration process
chloroform solutions are evaporated in water bath and pure
caffeine is obtained. In water insoluble method caffeine and oil
residue were obtained. The oil, in the residue part is removed
by hot water. Extraction process is performed by using
chloroform and the crude caffeine is obtained. From the results
of experiments, caffeine contents were found in classic, gold
and Turkish coffee as 1,450±0,050%, 1,027±0,102%,
0,400±0,010%, respectively. Caffeine contents which are
found in 1, 3, 5 and 7 cups of coffee are calculated.
Furthermore, the daily intake of caffeine from coffees that
affects human health is also investigated.
Fig.1 The coffee plant [7]
Keywords— Caffeine, health, coffee, water soluble-insoluble
Coffea arabica and Coffea canephora var. robusta,
commonly known as arabica and robusta, are the two coffee
varieties of highest economic and commercial importance [8].
Arabica coffee, with its lower bitterness and bitter flavor, is
more appreciated by consumers and it costs twice as much as
Robusta [9].
In Turkey, drinking Turkish coffee is a cultural behavior
that comes from Ottoman Empire and most of the people
consume this beverage every day [10]. Turkish coffee is a
method of preparing coffee. Roasted and then finely ground
coffee beans are boiled in a pot, usually with sugar, and served
in a cup where the grounds are allowed to settle (Fig.2) [11].
coffee.
I. INTRODUCTION
Coffee is one of the most popular drinks in the world due to
its unique flavor and sensory characteristics [1]. The homeland
of coffee is an area on the south of Ethiopia which is called
Kaffa [2]. Nowadays Coffee is cultivated in over 65 countries
around the world. The coffee producing countries are found in
the tropical zone because coffee trees need a lot of water and
humidity [3]. With extensive and wide spread cultivation of
M.B. Piskin, is with the Yildiz Technical University, Department of
Bioengineering, Davutpasa Campus, 34210 Esenler, Istanbul, Turkey (phone:
0090-212-3834776; fax: 0090-212-3834725; e-mail: [email protected]).
F. Demir, is with the Yildiz Technical University, Department of Chemical
Engineering, Davutpasa Campus, 34210 Esenler, Istanbul, Turkey (e-mail:
[email protected]).
A. S. Kipcak, is with the Yildiz Technical University, Department of
Chemical Engineering, Davutpasa Campus, 34210 Esenler, Istanbul, Turkey
(e-mail: skipcak@ yildiz.edu.tr / [email protected]).
O. Dere Ozdemir, is with the Yildiz Technical University, Department of
Chemical Engineering, Davutpasa Campus, 34210 Esenler, Istanbul, Turkey
(e-mail: odere@ yildiz.edu.tr).
E. Moroydor Derun, is with the Yildiz Technical University, Department
of Chemical Engineering, Davutpasa Campus, 34210 Esenler, Istanbul,
Turkey; e -mail: [email protected] / [email protected]).
http://dx.doi.org/10.15242/IIE.E1213014
Fig.2 Turkish coffee
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International Conference on Emerging Trends in Engineering and Technology (ICETET'2013) Dec. 7-8, 2013 Patong Beach, Phuket (Thailand)
II. EXPERIMENTAL PROCEDURE
In addition, other coffees types such as instant coffee are
also consumed beside Turkish coffee today. Instant coffee,
also called soluble coffee and coffee powder, is a beverage
derived from brewed coffee beans. Instant coffee is
commercially prepared by either freeze-drying or spray drying,
after which it can be rehydrated [12]. Today all types of
coffees are more important beverage not only in Turkey but
also all around of the world [13].
Coffee plant is the major sources of natural caffeine. The
caffeine content in coffee plant varies between 1 and 4% by
dry weight [14].
Caffeine (3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6 dione),
a purine alkaloid, is a key component in most popular drinks
especially tea and coffee [14]. (Fig.3)
A. Preparation of the Coffee Samples
Coffees were purchased from the local market in Istanbul,
Turkey. Classic, gold and Turkish coffees were selected for
the purpose of caffeine analyses (Fig.4).
Fig.4 Coffee samples
Selected coffees were separated as water soluble (classic
and gold) and water insoluble as Turkish coffee. Then these
two types of coffees caffeine contents were analyzed by using
two different methods.
B. Analysis of Water Soluble Coffee
Classic and gold coffees were analyzed by the method used
for water-soluble coffees. In this method, 2 g of coffee which
is the average value in a cup of coffee, was weighed and
brewed according to the standard of ISO 3103. (Fig.5)
Fig.3 Structure of caffeine molecule [1]
Natural sources of caffeine include different varieties of
coffee beans (Coffea canephora, Coffea arabica), tea leaves
(Camellia sinensis), guaraná seeds (Paullinia cupana), maté
leaves (Ilex paraguariensis), kola nut seeds (Cola nitida, Cola
acuminata) and cocoa beans (Theobroma cacao) [15].
Caffeine has many effects on the human health. The
commonly recognized effects include diuresis, increased
locomotor activity, vigilance, alertness, and arousal as well as
sleep disturbance. Furthermore, caffeine can increase blood
pressure, plasma catecholamine levels, and gastric acid
secretion [16].
The caffeine concentration in coffee is a popular issue for
the researchers due to health effects. Different coffee samples
and their caffeine content were investigated by the lots of
researchers. Wanyika et al. (2010) were determined levels of
caffeine in coffee using high performance liquid
chromatography (HPLC) and UV/ V is spectrophotometric
methods [13]. Extraction method was used by Macrae and
Dick (1983) and Noirot (1998) to analysis caffeine content [9].
Extraction method was also used by Bermejo D.V. (2012) to
determine caffeine content from coffee using a bio-renewable
agrochemical solvent [15].
The purpose of this study is to determine the content of
caffeine of the three types of coffee that are classic, gold and
Turkish coffee. Also how caffeine affects the human body is
investigated.
http://dx.doi.org/10.15242/IIE.E1213014
Fig.5 Brewed coffees
After brewing NaHCO3 (sodium bicarbonate) was added
and solution was poured into a separation funnel. The
separation funnel was rinsed by adding chloroform solution to
separate the two phases which is shown in Fig.6.
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International Conference on Emerging Trends in Engineering and Technology (ICETET'2013) Dec. 7-8, 2013 Patong Beach, Phuket (Thailand)
Fig.6 Two phase in the separator funnel
Fig.9 Condensation process
The bottom phase was taken into a beaker and MgSO4
(magnesium sulfate) was added. After a few minutes, solution
was filtered into a beaker. (Fig.7)
After the condensation process, the mixture was filtered and
the filtrate was evaporated on a water bath. After the
evaporation, residue of caffeine and oil was obtained which is
shown in Fig.10.
Fig.7 The filtered solution
The filtered chloroform solutions were evaporated in water
bath and pure caffeine was obtained. In Fig.8 the crude
caffeine is shown.
Fig.10 Residue of caffeine and oil
To separate the oil from the mixture hot pure water was
added to the residue of caffeine and oil. Then the mixture was
heated in a water bath and cooled to a room temperature.
KMnO4 (Potassium permanganate) solution is added into the
flask. After that H2O2 (hydrogen peroxide) solution was added
to remove the color of the solution. The mixture was heated in
water and allowed to cool to a room temperature.
After cooling, mixture was filtered (Fig 11). Filtrate was
poured into a separation funnel and rinsed by adding
chloroform solution to separate the two phases. The bottom
phase was taken into a beaker.
Fig.8 Crude caffeine
C. Analysis of Water Insoluble Coffee
Turkish coffee was analyzed by the method used for waterinsoluble coffees. In this method, ammonia solution was
poured to coffee in the flask. After a few minutes, chloroform
solution was added. Then condenser was placed on the flask
and allowed to stand on the water bath for 30 minutes which is
shown in Fig.9.
Fig.11 The filtration process
http://dx.doi.org/10.15242/IIE.E1213014
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International Conference on Emerging Trends in Engineering and Technology (ICETET'2013) Dec. 7-8, 2013 Patong Beach, Phuket (Thailand)
where MDI is the maximum daily caffeine intake.
The collected chloroform solutions are evaporated in water
bath and pure caffeine was obtained.
IV. DISCUSSION AND CONCLUSIONS
III. RESULTS AND DISCUSSION
Human daily maximum caffeine intake is given in Table II.
In Table II you can see the recommended maximum daily
caffeine intake amount which is 400-450 mg for adults. Also
the table shows us the caffeine amount for the early ages is low
compared with the adults.
A. Analysis Results
Analysis results are shown in Table I. From the results
obtained, the maximum caffeine content is seen in the classic
coffee, followed by gold coffee and Turkish coffee. The
average caffeine content in classic coffee is calculated as
1,450%. Also the average caffeine content in gold coffee and
Turkish coffee is analyzed 1,027%, 0,400% respectively.
TABLE II
MAXIMUM DAILY CAFFEINE INTAKE [17]
Recommended Maximum Daily Caffeine Intake (mg)
TABLE I
CAFFEINE CONTENT OF COFFEES
Coffee Type
Caffeine Content (%)
4-6 Years
45
7-9
60
10-12
85
Classic Coffee
1,450 ± 0,050
Women of Childbearing Age
300
Gold Coffee
1,027 ± 0,102
Adults
400-450
Turkish Coffee
0,400 ± 0,010
Caffeine is assumed to be the most widely consumed
behaviorally active substance in humans [18]. Caffeine
increases alertness and reduces fatigue. This may be especially
important in low arousal situations, but intake of high doses of
caffeine can cause negative effect such as anxiety, restlessness,
insomnia and tachycardia on the human body [19].
The caffeine contents of the analyzed coffees were calculated
for 1, 3, 5 and 7 cups respectively. Analysis data were
calculated with two different results such; as daily intake for
adults (mg) and percentage intake for adults (%). Results are
shown in the Table III and Table IV, respectively. According
to results obtained in this study, for all coffee types, the
amounts of caffeine in 7 cups are lower than the daily intake
for adults.
The reason of the small amount of caffeine in Turkish coffee
is that a large part of caffeine is remained in the sediment part.
According to the analysis method, caffeine content of filtrate is
calculated but the amount of caffeine of sediment isn't
determined. As can be seen from both Table I and Fig. 9,
caffeine content in Turkish coffees lower than the classic and
gold coffees.
TABLE III
DAILY CAFFEINE INTAKE FOR ADULTS
Daily Caffeine Intake (mg)
1 Cup
Fig.9 Caffeine contents of teas
Turkish Coffee
29
20,5
8
87
61,5
24
5 Cups
145
102,5
40
7 Cups
203
143,5
56
TABLE IV
DAILY CAFFEINE INTAKE FOR ADULTS
Daily Caffeine Intake for Adults (%)
Classic Coffee
(Eq. 1)
Amounts of caffeine in 1, 3, 5 and 7 cups of coffee, was
calculated and compared with 400-450 mg which is the
recommended maximum daily caffeine intake amount for
adults given in Eq. 2.
Gold Coffee
Turkish Coffee
1 Cup
6,44-7,25
4,5-5,13
1,77-2,00
3 Cups
19,32-21,75
13,50-15,39
5,31-6,00
5 Cup
32,20-36,25
22,5-25,65
8,85-10,00
7 Cup
45,08-50,75
31,5-35,91
12,39-14,00
Hancı et. al. were determined the contents of caffeine in
classic, gold and Turkish coffees using high performance
Daily Caffeine Intake for Adults (%)  B MDI 100 (Eq. 2)
http://dx.doi.org/10.15242/IIE.E1213014
Gold Coffee
3 Cups
B. Daily Dosage Calculations
Caffeine content of 2 g coffee was analyzed and extraction
data was expressed as percentage by using Eq. 1.
Caffeine content (%)  A 2 100
where A is the caffeine content of 2 g coffees.
Classic Coffee
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International Conference on Emerging Trends in Engineering and Technology (ICETET'2013) Dec. 7-8, 2013 Patong Beach, Phuket (Thailand)
[19] S. Gokulakrishnan, K. Chandraraj, Sathyanarayana N. Gummadi,
Microbial and enzymatic methods for the removal of caffeine, 2004.
[20] Silvarolla MB, Mazzafera P, de Lima MMA. Caffeine content of
ethiopian Coffea arabica beans. Genet Mol Biol 2000;23:213–5.
[21] Timo Rieg, Jürgen Schnermann, Volker Vallon, Adenosine A1 receptors
determine effects of caffeine on total fluid intake but not caffeine
appetite, 2006.
liquid chromatography (HPLC). 2 gr of coffee which is the
average value in a cup of coffee was analyzed in this method.
These results are shown in Table V.
TABLE V
RESULTS OF CAFFEINE CONTENT BY HPCL METHOD
Daily Caffeine Intake for Adults (mg)
Classic Coffee
Gold Coffee
Turkish Coffee
1 Cup
69
50
33,2
3 Cups
207
150
99,6
5 Cup
345
250
166,0
7 Cup
483
350
232,4
According to results of HPLC method caffeine content in 7
cups of classic coffee is higher than maximum value for adults
and caffeine content of gold and Turkish coffee in 7 cups are
lower than daily intake. As it is seen that Hancı et. al.’s results
are higher than this study. This situation is due to the different
types of coffees brewed in different regions and the difference
of experimental and HPLC method.
As a result the investigated Turkey brand of coffees; gold,
classic and Turkish coffee do not reach the maximum daily
dosage of caffeine concentration.
REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
http://tr.wikipedia.org/wiki/Kafein
http://www.turkishcoffeeworld.com/History_of_Coffee_s/60.htmhttp://
http://kahvetarifi.blogspot.com/2010/12/kahve-agac.html
megep.meb.gov.tr/mte_program_modul/modul_pdf/541GI0101
http://www.milk.mb.ca/nutritionOrder/pdf/Estimate your caffeine intake
for a day.
A. Smith, Effects of caffeine on human behavior, 2002.
Alonso-Salces, R.M., Serra, F., Reniero, F., Herberger, K., Botanical
and geographical characterization of green coffee (Coffea arabica and
Coffea canephora): chemometric evaluation of phenolic and
methylxanthine contents, 2009, J. Agric. Food Chem. 57, 4224–4235.
Astrid Nehlig, Are we dependent upon coffee and caffeine?A review on
human and animal data, 1997.
C.-L. Kya, J. Louarnb, S. Dusserta, B. Guyotc, S. Hamona, M. Noirota,
Caffeine, trigonelline, chlorogenic acids and sucrose diversity in wild
Coffea arabica L. and C. canephora P. Accessions, 2000.
David Villanueva Bermejoa, Pilar Lunaa, Marina S. Manic, Vesna
Najdanovic-Visak, Guillermo Reglero, Tiziana Fornaria, Extraction of
caffeine from natural matter using a bio-renewable agrochemical
solvent, 2012.
Fredholm, B.B., Battig, K., Holmen, J., Nehlig, A., Zvartau, E.E.
Actions of caffeine in the brain with special reference to factors that
contribute to its widespread use, 1999, Pharmacol. Rev. 51, 83–133.
H. Ashihara, A. Crozier, Caffeine: a well known but little mentioned
compound in plant science, Trends in Plant Science 6, 2001, 407–413.
H. N. Wanyika, E. G. Gatebe, L. M. Gitu, E. K. Ngumba and C. W.
Maritim, Determination of caffeine content of tea and instant coffee
brands found in the Kenyan market, 2010.
Illy, A., & Viani, R., Espresso coffee: The science of quality. London:
Academic Press, 2005.
International Food Information Council Foundation, Caffeine & Health:
Clarifying The Controversies
Mart´ın MJ, Pablos F, Gonz´alez AG. Discrimination between arabica
and robusta green coffee varieties according to their chemical
composition. Talanta 1998;46:1259–64
Nancy J. Frost-Meyera,, John V. Logomarsinob, Impact of coffee
components on inflammatory markers:A review, 2011.
Pushpa S. Murthy, M. Madhava Naidu, Sustainable management of
coffee industry by-products and value addition—A review, 2011.
http://dx.doi.org/10.15242/IIE.E1213014
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