· By Jonathan Parent
Drink more coffee, but less caffeine
An attraction for specialty coffees that have a low caffeine content has already been apparent for a few years. In 2017, the National Coffee Association reported that people between the ages of 18 and 24 were the biggest consumers of decaffeinated coffee, accounting for 19% of consumption in the United States. The desire to drink coffee throughout the day for the taste without excess caffeine is one of the main reasons.
In 1819, Friedlieb Ferdinand Runge, a German chemist, undertook work on coffee and put his finger on a particular compound which he named Kaffein. Caffeine is present in the seeds, leaves and fruits of various plants including guarana, yerba mate, tea and, of course, coffee. Although it takes various names depending on its origin, it is always the same C 8 H 10 N 4 O 2 molecule. Caffeine breaks down into three chemical compounds: theophylline, paraxanthine and theobromine. Once ingested, it crosses the blood-brain barrier, the one that separates the bloodstream from the rest of the body, to reach the brain. It acts mainly as a stimulant by binding to membrane receptors for adenosine. Adenosine is a neurotransmitter whose purpose is to slow down nerve activity and thus cause drowsiness. When caffeine takes the place of adenosine on the receptors, it leads, on the contrary, to an activation of neurons. There is then an increase in alertness and wakefulness. The stimulating effect of caffeine will also allow the release of adrenaline and the increase in the production of dopamine.
Why did coffee trees start producing caffeine?A 2014 study published in the journal Science shows how coffee plants evolved to produce caffeine. It started when a gene for an N-methyltransferase – an enzyme in the plant – mutated and then accidentally duplicated. This mutation caused the enzymes to act differently and play around with a compound called xanthosine. Introducing certain modifications – cutting off an arm of atoms and adding clusters of atoms – the enzymes transformed the xanthosine until it became caffeine.
Now, the production of this stimulant allows coffee trees to induce favorable behavior towards them in insects and animals. Caffeine is primarily defensive. It has the effect of repelling insects that would otherwise feed on the leaves. Some insects have even developed taste receptors (Drosophila) warning them of the presence of caffeine in order to avoid ingesting too much of it. In very large doses, caffeine can be toxic to them, either paralyzing or killing them. Strangely, coffee plants also use caffeine for the opposite effect: to attract certain pollinating insects such as bees. The latter, feeding on the caffeine-enriched nectar contained in the flowers, then spread the pollen. Once fed, these insects obtain positive effects (a kind of buzz, the study tells us), which intuitively encourages them to remember the smell of said flowers and to revisit them.
A final advantage of caffeine: when the leaves of coffee trees die and fall, they contaminate the soil with caffeine. Its presence on the ground prevents other plants from sprouting, which harms competition.
Photo - Simon Taylor, Coffea Arabica, London, 1774.
Can low-caffeine varieties of Coffea be counted on to eventually replace decaffeinated coffees?
Bourbon pointu, also known as Laurina, was discovered on Reunion Island at the beginning of the 19th century. It is so called because of the more elongated shape of the grains. Since then, this variety has been introduced in Brazil, which has enabled the Instituto Agronômico de Campinas (IAC) to continue research on it. These have led to the following observation: the low amount of caffeine makes the production of Laurina more fragile than other varieties of Arabica.
As we have seen, caffeine acts as a defensive system. A species of Coffea producing very little is in a position of vulnerability in relation to its environment. We also note that the Laurina variety is almost extinct. Fortunately, the IAC, the National Coffee Research Institute of El Salvador and Edgardo Alqipzar, an agronomist by training, continued to be interested in it and replanted certain plants discovered naturally on the island of Reunion, but also in Costa Rica. The fact remains that only 2 tonnes were produced in 2006, whereas in the 19th century the peak of Laurina production was reached at 4000 tonnes. A decline that cannot be denied!
Unlike Arabica which contains 1.4-1.8% caffeine, the Laurina variety has 0.2-0.3%. There is also the Aramosa variety which is more around 0.7 to 0.8%. They are therefore not decaffeinated, but what is called in English locaf.
Their production remains quite rare, since it is expensive and brings its share of difficulties given their fragility. On the other hand, everyone in the specialty world agrees that these two varieties offer exceptional cups.
Research and writing: Chloé Pouliot