Thursday, December 13, 2018
   
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Buchu

betulina2

Agathosma betulina (buchu) is an indigenous plant (growing specifically in the mountains of the Western Cape and occurring in the wild on the Groot Winterhoek).  It has been used over the centuries for its medicinal qualities and is now sought after in Europe as a natural food flavourant.





There are a number of different agathosma sub-species, including various fragrant garden plants.  Traditionally buchu (boegoe) has been used for wound treatment (due to its antiseptic qualities) and in tunctures (most notably the alcoholic tincture boegoebrandewyn) for stomach ailments.  Two plants have been cultivated for their oils: crenulata and betulina.  For a while, there was something of a gold rush around crenulata, as it was an easy plant to establish, its growth was strong and the oil yield was high.  Oil prices made it an extremely lucrative plant to cultivate and there are numerous stories of eager farmers uprooting existing ochards and grazing lands in order to establish hectares of crenulata.   Unfortuately, the market for crenulata was short-lived as it was soon established that the oil has a high level of pulegone, a potentially toxic component that makes the oil potentially unacceptable for human consumption.  Strangely, after the collapse of the crenulata market, the demand for this oil apepars to be returning.

buchu seedlings


The buchu oil that is generally regarded as acceptable for human use is that of betulina: this plant is hard to propogate (seed propogation must be undertaken under strict management in order for it to be successful), the mortality of young seedlings is high and the plants remain highly sensitive to over and under watering, and nutrition needs to be applied with care and under srtict supervision.  In addition thereto, betulina is the subject of intense poaching, with both wild and cultivated plantations being raided by unscrupulous poachers.  The problem lies with the buyers who are prepared to buy cut fresh buchu from persons who are obviously not farmers, with no questions asked.  This has resulted (for example) in the eradication of wild buchu from the Piketberg mountains.  Poaching can also have tragic consequences: a few years ago we had a young boy who was in a party of night-time poachers die on the mountain, when he fell in the dark.  Poaching is carefully monitored on the mountain; the location of our main buchu plantations are generally not apparent and the presence of any strangers on the farm is immediately investigated.




The oil of betulina is characterised by its high percentage of diosphenol and isomenthone, and its low pulegone content.  Total diosphenol (including pseudo-diosphenol) content should be near 25 %, with a low pulegone content (close to 5 %).  Our betulina oil has the following average composition:


Pinene-alpha 0.77
Sabinene 2.18
Limonene 21.55
Cineol - 1,8 3.18
Menthone 7.48
Isomenthone 22.64
Pulegone 5.83
Pseudo-diosphenol 10.13
Diosphenol 11.37



Betulina is a complicated plant to establish and sustain.  We have established a protocol over the years to manage the plants, although our first few years were marked by mistakes and high mortality.  Planting takes place in July: there are interesting theories concerning the effect of the moon on the development of the tap root of these tiny seedlings.  The plants are harvested once a year, in February: there is some indication that alternate harvesting (i.e. harvesting every second year) will have a beneficial impact on the level of pulegone in the oil.  It appears that the plants may react to the trauma of harvesting by increasing their pulegone levels to fight off infection, which remains at a heightened level for some time.


The oil yield from betulina is high (we have yields at around 0.7 %).  The oil is a light straw colour with a powerful and distinctive menthol nose.  The oil is not suitable for aromatherapy and is too powerful for home flavouring (one part per million will provide a black currant flavour).  The market for this oil is accordingly almost entirely overseas.


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