The World of Caffeine (44 page)

Like
Coffea arabica, Coffea robusta
flourishes between the Tropics of Capricorn and Cancer.
Coffea robusta
prefers rainfall of about 75 inches a year and temperatures of 60 to 80 degrees Fahrenheit. The biggest difference between the conditions favored by
Coffea arabica
and those favored by
Coffea robusta
is that
Coffea robusta
demonstrates a tolerance to more extreme conditions. Most notable is its ability to withstand humidity without succumbing to the bane of
Coffea arabica,
leaf spot disease
(Hemileia vastatrix)
.
⁹

Despite Laurent’s efforts on behalf of
Coffea robusta, Coffea arabica
remains the more widely grown, but many regions where temperature and humidity are high, especially those that have experienced the devastation of leaf spot disease, have been replanted with
Coffea robusta. Coffea robusta
coffees are now the major species grown in the less mountainous regions closest to the equator. African varieties of
Coffea robusta
today represent more than 25 percent of all coffee used in the United States and Europe.
¹⁰

Those embarked on an ongoing hunt for the best cup of coffee should find it tantalizing to discover that there is a species superior to
Coffea arabica
—declared by many to be the species of genus
Coffea
producing the most aromatic and flavorful coffee beans in the world—that is currently unavailable and likely to remain so for the indefinite future.
Coffea stenophylla,
by historical accounts, was considered superior to
Coffea arabica
in a number of important respects: It is a hardier plant, it produces a larger crop, and, most importantly for the coffee connoisseur, the brewed beans have a richer taste. In these respects
Coffea stenophylla
would seem to combine the advantages of both
Coffea arabica
and
Coffea robusta
and go them each one better. But bad timing doomed
Coffea stenophylla
to the limbo of uncultivated crops. The plant was discovered growing wild in Sierra Leone and introduced to various English colonies in 1895, at the same time that a massive epidemic of rust disease was eradicating many plantations. To recover from the blight, the farmers needed a plant that would turn out a crop as quickly as possible. This pointed them away from
Coffea stenophylla,
the main disadvantage of which is requiring nine years to reach maturity, two years longer than
Coffea arabica
and five years longer than
Coffea robusta.
As a result, even though it’s hardier and it produces more beans once it gets started,
Coffea stenophylla
has never gained a foothold in the marketplace.
¹¹

It has been reliably determined by French and German investigators that several species of
Coffea,
including
Coffea
gallienii, Coffea bonnieri, Coffea mogeneti,
which grow wild in the Comoro Islands and Madagascar, are absolutely caffeine free. However they contain a bitter substance, cafamarine, that makes their beans unfit for use.
¹²

A tea was and still is prepared from the leaves of the coffee plant, most notably in Arabia, Sumatra, and the West Indies. It is infused from the roasted leaves of the coffee tree in the same manner as regular tea, and it is preferred, where consumed, to coffee brewed from the bean.
¹³
In Sumatra the bean crop was frequently ravaged by insects, and the growers, seeking a substitute that would contain caffeine, collected the leaves in their stead. The discovery that the leaves are high in caffeine was exploited during World War I by Dutch factories, who bought them by the ton in order to extract the stimulant for use by combat troops.

Another sort of coffee tea is a peninsular habit of Arabia and has been since at least the middle of the sixteenth century. In the land from which the coffee bean came, a beverage, commonly preferred in summer because of its “cooling” humoral
properties, and exclusively consumed by the discriminating, was brewed from the husks of the bean. The decoction is said to resemble a sort of spicy, aromatic tea more than it does either modern Western or Turkish coffee.

The Kentucky Coffee Tree
(Gymnocladus dioica)
is a plant native to central and eastern North America and eastern China. Settlers ground the seeds to make a drink with some resemblance to coffee. Like guarana and yoco, these plants contain latherproducing saponin, but, unlike them, do not contain any caffeine.
¹⁴

In sum, the primary botanical differences between the most popular and widely used coffee plants,
Coffea arabica
and
Coffea robusta,
are these:
Coffea robusta
will grow at relatively low altitudes, will tolerate higher temperatures and heavier rainfall, demands higher soil humus content, and is generally more resistant to disease.
Coffea arabica
beans are oval and green to yellowish green in color, while
Coffea robusta
beans are rounder and tend toward brownish shades. Of course the most important difference between the two species as far as coffee drinkers are concerned is that coffee made from
Coffea
arabica
tastes and smells much better. Avicenna, the great Arab philosopher and physician, may have gotten it right a thousand years ago when he recommended beans “of a lemon color, light, and of a good smell.”
¹⁵

There are many ways of classifying the drinks called “teas” and a bewildering variety of names for dozens of different types: black, green, oolong, China, Assam, flavored, scented, decaffeinated, tonics, barks, decoctions, infusions, and ptisanes, and an entire lexicon of trade names, such as “English Breakfast tea.” These rubrics codify differences in botanical varieties, growing conditions, admixtures, and methods of processing tea, but also include many drinks made exclusively from herbs and plants that are botanically unrelated to tea.

In simple fact, the tea leaves used in brewing tea grow on a single species,
Camellia sinensis,
a plant native to northern India, Tibet, and possibly China, regions where it is still chiefly cultivated. Yet because of ignorance about the differences produced by different processing methods and the fact that
Camellia sinensis
boasts a great number of varieties, or subspecies, for centuries there was considerable confusion as to whether there was one or more species of the plant. It was not until 1958 that botanists agreed internationally that there was one species with many varieties. Two of these varieties, Assam and China tea, have major commercial importance.

The two-hundred-year-old confusion over how to classify the tea bush began with the father of all botanical nomenclature, Carl von Linné (1707–78), or Carolus Lin-næus, Swedish botanist and inventor of the twofold naming system for classifying plants (which supplanted the clumsy Latin phrases employed previously) that is still used today. In
Species Plantarium
(1753), Linnæus divided tea into two species: the
viridis,
which produced green teas, and the
bohea,
which produced black.

Engraving from Dufour,
Traitez Nouveaux
. This French engraving shows two Chinese farm workers with their wicker baskets harvesting “Chinese tea on the bush” in the highlands, an exotic image for the seventeenth-century European audience for whom it was created. (The Library Company of Philadelphia)

However, as stated above, it is now accepted that all tea, including both the prolific Assam
(assamica)
and the hardy China
(sinensis)
teas, are varieties of a single species,
Camellia sinensis
.

The bewilderment over the meaning of tea types has been exacerbated by the fact that there are three distinct methods of processing tea leaves, each resulting in a recognizably different product: black tea, green tea, or oolong tea. Black tea (called “red tea” in China, after the color of the beverage rather than the darker color of the dried leaves) is created when fresh green leaves are withered after plucking, spread out to dry, and then crushed by rollers to bring out the aromatic oils; the crushed leaves then oxidize, or ferment, and assume their characteristic brown color. Green tea is produced by firing or steaming the fresh leaves immediately after picking, a step which prevents the leaves from oxidizing and precludes the natural fermentation that would otherwise occur. Oolong tea is prepared like black tea, but its leaves are allowed to ferment for only a short time before drying and turn only partially brown, acquiring a flavor that shares something of both black and green teas.
¹⁶

The divisions of black, green, and oolong tea are based entirely on these differences in processing. It is possible to make all three kinds from the same tea bushes, something which is often done. However, certain regions typically specialize in producing a certain type, and because of this people often mistakenly think the tea grown in each place is botanically distinct. For example, virtually all Japanese tea is green, almost all Indian tea is black, while China produces green, black, and oolong tea.

All types of tea, as they are commonly prepared, contain less caffeine than coffee. Black tea infused for five minutes contains about 40 to 100 mg of caffeine in each cup; if infused for only three minutes it contains about half this amount. Green tea has less caffeine than black. Tea bags, because they contain broken leaves, produce a drink that contains more caffeine. In addition to caffeine, tea contains polyphenols, commonly known as “tannins,” and aromatic or essential oils. In China, medicines are made from the tannins to treat a variety of diseases including kidney and liver conditions. The essential oils are the source of tea’s distinctive aroma and reputedly act as a digestive aid. Green tea contains more essential oils than black, which typically loses some of these in its longer processing, and therefore green tea has a stronger scent.
¹⁷

In the first half of the eighteenth century, when Linnæus undertook his lifework of classifying flora in accordance with a twofold scheme of his own devising, the world was a much bigger place than it is today. The great scientist’s acquaintance with the tea plant was limited by Chinese restrictions on foreign travelers and the unreliability of untutored observations of laymen who had somehow completed the difficult journey. Driven by scientific curiosity, Linnæus made a deal with the Swedish East India Company according to which one of his students would annually sail with the fleet for China and would so be able
to return with specimens and accurate information about local conditions. Getting his hands on a tea plant, however, proved to be more difficult than he had originally thought.

Linnæus’ initial hopes rested on the shoulders of a young student, Per Osbek, who, like most of Linnæus’ mariner protégés, served as ship’s chaplain to pay for his food during the voyage. Although Osbek returned with a profuse variety of plants and pages of detailed observations, his attempt to deliver a tea plant was defeated by misadventures. One plant was knocked into the sea when Osbek’s crew fired the ship’s cannons in the traditional salute on departure. On a second voyage, he managed to bring a plant within sight of the Cape of Good Hope, only to watch it blow overboard during a sudden storm that recalls the one that menaced de Clieu and his coffee plant on his return to Martinique.

Succeeding efforts fared no better. A contemporary of Linnæus, Magnus von Lagerstroem, a director of the Swedish trading company, was proud of the plant he carried from China to Uppsala, Sweden, where it was cultivated for two years before it was found to be not a tea plant at all, but another species of
Camellia
. A genuine tea plant was in fact delivered to Uppsala only a short time thereafter, but, because it was so valuable on arrival it was placed in the commandant’s room for safekeeping, where it was promptly devoured by rats.

Success finally came in 1763. In that year a ship commanded by one Captain Eckburg returned to Sweden from China with potted seeds that germinated and sprouted during the trip home. Even here fate intervened, for when on arrival Eckburg sent half the plants to Linnæus in Uppsala, they were destroyed in transit. The remaining half, however, he carried to Uppsala himself, and on October 3, after years of trying, Linnæus became the first man in Europe to possess growing tea plants.
¹⁸

Camellia sinensis
is an evergreen bush or treelike shrub that resembles a myrtle tree, partly because of the conical shape of its leaves. Every spring, it yields fragrant white blossoms, about an inch in diameter, similar in appearance to apple blossoms or wild roses. Each blossom becomes a fruit, about an inch in diameter, inside of which grows one to three seeds, a little smaller than apple seeds, in each of four cells.