Jamaican Coffee - the finest in the world!

What is involved in going from the ripe beans, to the roasted beans, to end up as a finished product?

coffee pictures

Have you heard so much about synthetic as opposed to "natural" or "organic" chemistry and are starting to wonder whether it all happens like the right hand side of the above picture?

Then read on....

Apart from the Chemistry below, did you know that:
There are a number of varieties of both arabica and robusta.
In Jamaica, only arabica is grown and according to the 1953/1983 Regulations
"blue mountain coffee means: coffee that is grown in the Blue Mountain Area as described in the Schedule; and processed or manufactured at any coffee works specified in the Schedule and to which a licence granted pursuant to regulation 5 relates."
The quality of the beans is graded into Blue Mountain No. 1 - 3, Pea Berry and Triage. Other grades of Jamaican coffee include: High Mountain Supreme, Jamaica Prime and Jamaica Select. In its wild state, the shrub grows to about 8 to 10 metres.

Although Jamaica does not have much of the world market in terms of production (International Coffee Organisation) , the beans are well known for their exceptional quality and Blue Mountain coffee commands extremely high prices. Blue Mountain Peak stands approximately 2256 m (7402 feet) high, the average rainfall for Jamaica is about 198 cm (78 inches) and the average temperature is 27 C (82 F). Together with sunshine every day and good soil, it all contributes to not only great coffee but the land of "wood and water" presents an incredibly beautiful environment to live and work in.

A brief history of Jamaican coffee from the Jamaican Coffee Industry Board or the Jamaican Gleaner History series

It is interesting to note that coffee arabica was characterised by Linnaeus in 1753 by which time Jamaica had been growing coffee for 25 years.

Coffee Chemistry

For simplicity, this will be subdivided into sections.


A range of carbohydrates, including polysaccharides and the low molecular weight sugars (mono-, di- and trisaccharides) are found in green coffee.
Sucrose is the major free sugar present and for arabica is present at about 8% on a dry basis.
Polysaccharides (glycans) amount to up to 50% on a dry basis of green coffee. Hydrolysis of coffee polysaccharides has been shown to give mannose >> galactose > glucose >> arabinose.
On roasting the coffee major changes occur, depending on the degree of roasting, e.g. from light to dark and simple sugars such as arabinose are progressively destroyed.

Nitrogenous Components

These may be described in terms of three main groups of compounds: alkaloids, trigonelline together with nicotinic acid and amino acids and proteins.


Caffeine is perhaps the best known and controversial alkaloid found in coffee and it is present at about 1-2% on a dry weight basis in arabica.
An alternative view (random dot 3D image) of the caffeine molecule can be found here.


Trigonelline has received considerable attention as a nitrogen containing component of coffee due to its reported antitumour activity.
It is present at about 1% on a dry weight basis but it is thermally unstable and hence can lead to other nitrogenous materials upon roasting such as pyridines and pyrroles.
A note on the effect of the roasting process on the presence of trigonelline is available on-line.

Chlorogenic Acids

Quinic acid is one of the dominant acids found in the coffee bean. It occurs as both the free acid and as esters, mainly with caffeic acid. Immature green coffee beans contain considerable amounts of these 5-chlorogenic acid derivatives.

Volatile Components

The analysis of the volatile material is usually achieved by initial separation using Gas Chromatography or HPLC. For example, headspace analysis methods involve sampling the vapour phase which is directly above the sample.

An indication of the diversity of the composition of roasted coffee can be seen from the numbers given in the Table below, which highlights the sensitivity of the GC/MS detection method.

Flavour Constituents in Roasted Coffee Aroma

Type Number
furans 99
pyrazines 79
ketones 70
pyrroles 67
hydrocarbons 50
phenols 42
esters 29
aldehydes 28
thiazoles 28
oxazoles 27
thiophenes 26
amines + N-containing 24
alcohols 20
acids 20
sulfides + S-containing 16
pyridines 13
not classified 9
lactones 8
Total 655

The following sensitive map is a simulation of a GC/MS, the GC, in JCAMP-DX format, of roasted coffee can be downloaded. It was originally created for those running Windows who had the MDL Chime plugin installed (now obsolete) and was a very early example of an interactive Chemistry enhanced web page. By selecting a numbered box the Mass Spectrum (or MOL if the MS is unavailable), was downloaded for that constituent.

More recently, alternative methods using a JCAMP-DX display of a simulated GC either with JSpecView vs 1 and JSpecView vs 2 and Jmol have been produced as well.

GC/MS of coffee

Only the more intense peaks have been shown and they have been identified as:

Peak No. FEMA code Chemical
1 (NA) 2-methylfuran MOL or MS
2 (2170) 2-butanone MOL or MS
3 (NA) 2-methylbutanal MOL or MS
4 (NA) 2,5-dimethylfuran MOL or MS
5 (2370) 2,3-butanedione MOL or MS
6 (3523) pyrrolidine MOL
7 (2841) 2,3-pentanedione MOL or MS
8 (NA) 2-methylthiophene MOL
9 (3407) trans-2-methyl-2-butenal MOL
10 (NA) 4-methyl-2,3-pentanedione MOL or MS
11 (NA) 3-methyl-1-hydroxybenzene MOL
12 (NA) pyrazine MOL
13 (NA) furfurylmethylether MOL
14 (3309) 2-methylpyrazine MOL or MS
15 (2170) 2-butanol-3-one MOL
16 (NA) 1-propanol-2-one MOL
17 (3272) 2,5-dimethylpyrazine MOL or MS
18 (3273) 2,6-dimethylpyrazine MOL or MS
19 (2489) furfural MOL or MS
20 (NA) ethyleneglycol diacetate MOL
21 (NA) furfuryl formate MOL
22 (3163) 2-acetylfuran MOL
23 (3386) pyrrole MOL orMS
24 (NA) 1-(2-furyl)-2-propanone MOL
25 (2490) furfuryl acetate MOL
26 (2702) 5-methylfurfural MOL
27 (2491) furfuryl alcohol MOL or MS

The numbers in the second column are the FEMA codes (Flavor and Extract Manufacturers' Association of the USA) as found in the Aldrich Flavors and Fragrances Catalog.

Most of these volatile compounds are derived from pyrolysis or from reactions occurring during the roasting of the raw bean. These reactions involving sugars, amino acids, organic acids and the phenolic compounds give rise to the characteristic aroma and flavour associated with the different types of coffee. The nature of the volatile compounds and the exact composition found is dependent on a variety of factors that include the location during growth (eg climate and soil conditions), the storage of the beans (both during harvesting and subsequent to roasting) and the roasting conditions used (type of equipment, time and temperature).

Aroma Chemistry is described at the Coffee Research Institute site maintained by Michael Griffin.

Carboxylic Acids

Aliphatic carboxylic acids play a large role in the quality of coffee and coffee infusions. Changes in pH can lead to ionisation of functional groups (eg phenolic hydroxy groups) and this can alter the flavour of the product.
A number of acids reported to be present in coffee have characteristic flavours and their thresholds in aqueous solution may be as low as under 10 ppm. For example, 2-Methylvaleric acid is reported to impart a flavour of cocoa or chocolate, whereas pyruvic acid gives rise to a burnt caramel flavour.
In green coffee, non-volatile acids such as citric acid, malic acid, oxalic acid and tartaric acid make up less than 2%.
In roasted coffee, over 30 aliphatic acids have been identified. These include 15 non-volatile monocarboxylic acids C1-C10, whilst the remainder are volatile. In general, the darker the roast, the lower the acid content.

Acid Chemistry is described at the Coffee Research Institute.

A list of chemicals identified in coffee seeds or leaves has been compiled by the USDA - ARS - NGRL, Beltsville Agricultural Research Center, Beltsville, Maryland

To learn more about the chemistry of coffee, see:
"Coffee" Volume 1:Chemistry. Edited by R.J. Clarke and R.Macrae,
Elsevier Applied Science Publishers, London and New York, 1985.

"Coffee: Recent Developments"
By: R Clarke (Consultant, Winchester, UK) and O G Vitzthum
ISBN: 0632055537, World Agriculture Series, USA, Apr 2001.

"Coffee Flavor Chemistry" by Ivon Flament,
ISBN: 0471720380, John Wiley & Sons (December 11, 2001).

"Volatile compounds in foods and beverages" , Ed by H. Maarse, Marcel Dekker, Inc, New York, 1991.

The proceedings from the The International Association on Coffee Science conferences.

The Coffee Berry Borer

In 1994, the Jamaica Coffee Industry suffered losses estimated at over J $ 70,000,000, due in part, to borer infestation. The Coffee Berry Borer originated in East Africa and was first reported in 1867. Its first appearance in the Caribbean was not reported until 1971.
It appears that endosulphan, the pesticide used to spray the shrubs, may not be as effective as once thought and in fact, a mutant form of the insect seems to be resistant. This new form was found in New Caledonia and has NOT yet been seen in Jamaica.
In Jamaica, the recommended dose of endosulphan is 600-800 ml / 200 l water.
The Gleaner, Saturday 17th February, 1996 page 4C.

Production Figures

The crop year is from 1st August to 31st July of the following year.


Blue Mtn




Crop year




US $





















In 1997, the retail price of Blue Mountain coffee in Japan ranged from US$ 100 to $130 per kilogram compared to $20 to $40 for the blended Blue Mountain coffee. The blend is governed by Japanese regulations and must contain at least 30% of Jamaican coffee once the Blue Mountain name is used.

The figures show the increasing trend in production of Blue Mountain coffee and reveal the need for more lowland coffee. The Japanese companies are now forced to use Blue Mountain in their blends with Colombian and Brazilian coffee due to the shortage.

The Gleaner, Sunday 8th June-1997, pages 8 and 11A.

The answers to some Frequently Asked Questions about coffee and caffeine have been collected by Alex López-Ortiz and Daniel Owen.
The National Coffee Association in the USA has sponsored a site to give more information on coffee.

link to butdione.jdx link to pendione.jdx link to pyrazine.jdx link to mpeddione.jdx link to mepyraz.jdx link to furfural.jdx link to furfacet.jdx link to mefurfur.jdx link to furfuryl.jdx link to mefuran.jdx link to d26mepz.jdx link to coffhd.jdx
article on coffee from Britannica
Return to links to the chemistry of other Jamaican items, including spices and fruit and vegetables.

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Copyright © 1995-2014 by Robert John Lancashire, all rights reserved.

Created and maintained by Prof. Robert J. Lancashire,
The Department of Chemistry, University of the West Indies,
Mona Campus, Kingston 7, Jamaica.
Created Feb 1995. Links checked and/or last modified 8th August 2014.
URL http://wwwchem.uwimona.edu.jm/lectures/coffeeJS.html