Friday, April 22, 2016

Gordonia yunnanensis: Potential Temperate Caffeine Crop

I think the plant Gordonia yunnanensis (Camellia taliensis) could be a good source of caffeine for home gardeners, perhaps even orchardists, in temperate climates such as Wellington, New Zealand.

This attractive tree has long been used for tea, collected from the wild, in the Yunnan Province of China (1). It has only recently become widely available in the nursery trade elsewhere, it also appears that it was only discovered to contain caffeine as recently as 1984 (2). Presumably communism kept it unavailable and little known to outsiders until very recently.

So far there seems to be little interest in this plant as a caffeine crop, which seems a little surprising given the economic importance of "mildly" addictive caffeine, found in very few plant species. As far as I'm aware it has been marketed exclusively as an ornamental not a caffeine/tea source in the nursery trade. I am also not aware of any books or sites recommending it as a caffeine source for home gardeners, only sparse scientific texts and the odd traveler seem to refer to use as tea. Conceivably the recent name change from Camellia taliensis to Gordonia yunnanensis has not helped, I'm not aware of a reference associating the new name with caffeine or tea.

The plant pictured has been in my garden, largely neglected, in Wellington, New Zealand, for about a year.  It has not minded winter with night temperatures usually around 3 C, sometimes down to -5 C . It also seemed to be oblivious to a very dry summer and below average, fairly hard clay soil. Some other plants I gave much more care to did not do so well, losing up to half of their leaves. Perhaps I over-fertilized them, a potential problem with the related tea plant.

I have not had the plant long enough to judge how productive they are, growth was impressive in spring but so far very slow at other times. Determining productivity is my main objective in the next few years.

I tried a few cups of tea from the leaves, it seemed to taste better than standard (Camellia sinensis) tea to me which I don't like much, it also didn't appear to be astringent like tea, but my perception could easily have been warped by my enthusiasm for this new discovery.  There are (probably more objective) comments on the net saying it doesn't taste that good, to me this is a minor problem if you think producing your own caffeine is more desirable than getting the third world to grow it for you and having corporations ship it around the world for you.  Plenty of tasty things could be grown and brewed with it to improve its rather bland, mild flavor if that's an issue. In my opinion almost any flavor associated with something addictive starts to taste mighty good over time, look at beer, tobacco or wine.

I chewed the raw flowers (without swallowing) thinking they might be edible like the related Camellia japonica.  After about a minute they produced a kind of burning sensation at the top of the mouth right at the back lasting about five minutes, tangy, perhaps like oxalic acid multiplied many times. I infer from this they are not edible raw. It is conceivable they'd be edible if dried and cooked as is apparently always done with Camellia japonica but I won't be trying that any time soon.


2) Teas, Cocoa and Coffee: Plant Secondary metabolite and Health. Crozier, Ashihara, Toma-Barberan 2011

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