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On July 20, 2016 in MyNews24, I reported on the following: “South Africa's own White Crystal grape (Kristaldruif) – its ancestry revealed for the first time!”
Now, the hunt is on in South Africa to try to locate the elusive second parent of White Crystal (Kristaldruif), namely, Krystalli (a.k.a. Kristalli), which was originally a Greek white table grape variety.
Recently, a photograph of a 150-year old “White Crystal” grapevine appeared online on Platter’s Website (April 5, 2016): http://www.wineonaplatter.com/blog/post/16838;jsessionid=799DA5972ABD990CF15BE6434603494E)
That 150-year old “Crystal grapevine” which is still growing in Robertson may have been incorrectly identified, and is most probably the original Greek Krystalli cultivar for the following reasons:
(a) The shape of the grapevine’s leaves appear to be somewhat different. The adult leaves of the Robertson grapevine generally show an ‘open’ petiolar sinus, whereas the genuine White Crystal petiolar sinus of adult leaves is mostly 'closed'.
(b) The size and/or weight of the grape berries also seem to be quite different. According to the photograph on Platter’s website, it appears that the grape berries are much larger than those of White Crystal as reported by Prof. Perold in his Treatise on Viticulture published in 1927. Prof Perold states in his Treatise that the White Crystal grape berries “…are spherical, medium…” This would imply an average berry weight of approximately 3 g. The average berry weight of Platter’s 'Crystal' seems to be approximately 4 – 5 grams. Therefore Platter’s 'Crystal' grape would be described as being 'medium large' to 'large'. It is very interesting that the official Greek Vitis Database reports a Krystalli berry weight of 3.6 – 5 grams (average 4.3 g).
This could very well be one of the reasons why the American viticulturist F. T. Bioletti, who had been appointed as a temporary lecturer at the Elsenburg College of Viticulture, Enology and Horticulture in the Cape Colony, South Africa between 1901-1904, wrote in a letter to the editor of California’s Pacific Rural Press in 1904 that: “The Crystal is a large white grape of very fine appearance but flavorless and a poor shipper.” In my mind it is quite apparent that he was describing the Greek Krystalli cultivar which at that time would naturally have caused much confusion because the two cultivars, i.e. 'Krystalli' and 'White Crystal' have a very close relationship with one another – after all, we now know that White Crystal is the offspring of Krystalli.
(c) It is interesting that Platter’s website describes the 150-year old vine in Robertson as: “…the vine is also noteworthy for having resisted phylloxera and other diseases over the decades and today standing on its original root system…”.
This aspect is not surprising because in Crete, where the Krystalli is indigenous, it has the reputation of having resisted the phylloxera plague that invaded that Greek island about 140 years ago. There are Krystalli vines that can be found there that are growing on their own root systems, i.e. not grafted onto American rootstock. It is obvious that because Sémilon (which is White Crystal's other parent) is not resistant to phylloxera, it would naturally follow that Krystalli would be more resistant to phylloxera than its White Crystal offspring.
(d) Finally, I have noted that on Platter’s website they report that in 2015 a batch of wine was made – but that it was not possible to make ordinary wine from those grapes. Although they claim that the 2015 harvest was an excellent one, the type of wine produced was one made in 'jerepigo' style – as they put it by: “… simply to briefly macerate it on the skins and then fortify it with spirit, jerepiko style.”
This style of wine making avoids the depletion of the grape glucose because it is only partially fermented. Now, one of the reasons for resorting to this type of method of wine making is when the grape harvest has not attained a sufficiently high level of grape sugar (usually measured in °Brix). This would happen with a cultivar such as Krystalli because it has been reported in the Greek Vitis Database that Krystalli will only reach a maximum sugar level of approximately 16°Brix – 18°Brix. This level of sugar is not enough to produce a stable dry white wine. So, either more sugar needs to be added before fermentation or one must fortify the must with alcohol in order to preserve it. They have opted for the second method (Jerepigo) because it is illegal to add sugar to the must. On the other hand, White Crystal is known to accumulate a high sugar level because of the smaller berries, and a sugar level of 20°Brix – 24°Brix is not unusual. This sugar level is ideal for creating a dry white wine from White Crystal grapes.
So, in conclusion, I would say that there is a strong probability that the Robertson 150-year old grapevine is a 'clone' of the original Greek cultivar called Krystalli.
I would therefore recommend that instead of an ampelographic analysis (e.g. comparing leaf shape, berry size etc.), a Microsatellite DNA (Simple Sequence Repeat or SSR) analysis should be performed on the 150-year old vine in order to determine its true identity.
Well, now the search for 'Krystalli' in South Africa is really on...I wish you all Good Luck!
By Jerry Rodrigues (26 July 2016)
