The science journal Nature recently ran a great article outlining the problems in growing an ultra-low or caffeine-free variety of coffee, particularly one that would be commercially-viable. It goes over the pitfalls of various attempts at developing and cultivating a species or strain of Coffea that would produce naturally caffeine-free beans, including hybridization and genetic engineering.
Decades of study have clarified how Coffea plants synthesize caffeine, the alkaloid that provides a measure of pest control to the plants. But manipulating the genes in Coffea arabica has not resulted in plants that reliably produce caffeine-free beans.
There are over 100 species of Coffea, and quite a few produce little or no caffeine. I wrote about one caffeine-free species from the Cameroon, described in 2008. Genetic compatibility problems have proven a barrier in transferring the caffeine-free property from other species to Coffea arabica. Wild, low-caffeine species of coffee have other bitter alkaloids that stand in for caffeine as pest protection, so cross-breeding with arabica has resulted in low cup quality. Individual plants of Coffea arabica that produce little or no caffeine have also been found, and arabica seeds have even been soaked in chemicals to induce mutations. Still, cross-breeding, cloning, and other techniques have so far failed to produce coffee with enough of the right stuff and less of the wrong stuff.
The article is open access, and I’ve included a list of related scientific literature below for more information.
Campa, C., Doulbeau, S., Dussert, S., Hamon, S., and Noirot, M. 2005. Diversity in bean caffeine content among wild Coffea species: evidence of a discontinuous distribution. Food Chemistry 91:633–637.
Mazzafera, P., Baumann, T. W., Shimizu, M. M., and Silvarolla, M. B. 2009. Decaf and the steeplechase towards decaffito—the coffee from caffeine-free arabica plants. Tropical Plant Biology 2:63-76.
Nagai, C., Rakotomalala, J. J., and Katahira, R. 2008. Production of a new low-caffeine hybrid coffee and the biochemical mechanism of low caffeine accumulation. Euphytica 164:133–142.
Ogita, S., Uefuji, H., Yamaguchi, Y., Koizumi, N. and Sano, H. 2003. RNA interference: Producing decaffeinated coffee plants. Nature 423: 823.
Silvarolla, M. B., Mazzafera, P. and Fazuoli, L. C. 2004. Plant biochemistry: A naturally decaffeinated arabica coffee. Nature 429:826.
Photo by Chris Brown (zoonabar) under a Creative Commons license.