Plop or Crack?

A perusal of the wines on sale in Nairobi’s supermarkets reveals that less than half are sealed with traditional cork. This is no surprise as it is common knowledge that for more than a decade the humble cork has been losing ground as the stopper of choice. Cork reigned supreme for centuries and the gentle plop sound made as it is pulled from the bottle is for many a vital component of the pleasures of drinking wine. The theory goes that corks will continue to disappear and in the foreseeable future will only be used for those rare and expensive first growth wines from Europe. It is the screw cap that is gaining dominance replacing the plop with a crack as a simple twist is now all that is needed to open many wine bottles.

The use of corks to provide a seal for wine containers, usually wooden barrels or clay jugs, goes back to the Ancient Greeks and Egyptians. Interestingly though by medieval times cork was not commonly used in Europe as a seal for wine containers. The reasons for this are speculative, but some scholars have postulated that the conquering of Iberia by the Moors in the 8th Century, which was then as is now the main supplier of cork, put a halt to supplies. The use of cork began to increase with the development of glass bottles during the 17th Century. Firstly glass stoppers were used, which involved the expensive and skilled process of grinding a glass bung to fit the neck of the bottle in much the same way as in a decanter. Cork quickly replaced glass stoppers principally because they were and still are relatively cheap. Since the 17th Century cork has been the dominant form of seal, and only began to wane in popularity towards the end of the 20th Century.

Cork is undoubtedly a remarkable product. It is natural and sustainable as well as relatively cheap and has the vital quality of being porous. The porosity not only enables the cork to be squashed and pushed into the bottle neck where it expands to form a snug fit, but also allows an almost infinitesimal amount of air to enter the wine. Science has demonstrated that this interface between the wine and air is critical for the maturation and development of nuisances in the wine so loved by connoisseurs. In reality it is only that tiny quantity of fine wines that really benefit from bottle ageing.

Corks qualities and strengths are in part also part of their problems. Cork unsurprisingly derives from the cork tree, Quercus suber, a relatively young species of oak. The thick bark is stripped with no detrimental effect on the health of the tree and cut into corks. Historically corks received little if any further treatment prior to being bunged into the bottle. As a natural product cork contains all sorts of chemicals including residues of sap. Wine makers became quickly aware that living cork while pliable and forming a good seal also reacted with the wine not necessarily with desirable effects.

Modern producers to combat cork taint normally bleach corks in a strong chlorine solution prior to washing and drying in an attempt to create a more inert product. It is possible though to detect the smell of chloroanisoles such as Trichloranisiole or TCA, on a wine even at almost infinitesimal concentrations. Professional wine tasters develop an ability to detect technical flaws in a wine such as the smell of TCA and can distinguish this smell from other odours emanating from other faults such as for example Brettanomyces (a form of yeast genera) contamination. Best quality corks are more likely to be free of TCA residues although they are of course expensive, which partly explains the change to other forms of seals. Wine tasters use the term corked to describe the smell and taste of a wine contaminated by a faulty cork. The term corked is also used wrongly, at least in wine tasting terms, to describe bits of cork floating around in the glass. Wine in a glass may indeed be literally corked as it contains little bits of cork, but the fault is a result of the acts of the corkscrew and the ineptitude of the pourer and not necessarily a faulty cork.

In Nairobi there are few if any restaurants that employ a sommelier. It is though quite common for a waiter to proffer a small amount of wine to undertake the tasting ritual. Diners are familiar with this ritual the uncomfortable and often pretentious scenario where the recipient of the proffered wine swirls, sniffs, and tastes before declaring wine suitable. The waiter then proceeds to fill the glasses of the dinners around the table. In Nairobi most waiters like to fill glasses as full as possible deeming it impolite to fill the glass half-full as a wine taster would prefer.

Strictly speaking although the tasting ritual is necessary it is usually carried under a misconception. Many believe what they are doing by tasting the wine is to determine if they like it or not. In reality what the diner should be doing is determining that the wine quality is good: in other words that the wine is not corked. To achieve this it is nine times out of ten sufficient to merely asses the wines appearance and smell as this reveal without tasting any faults. If a fault is detected then of course it is perfectly reasonable to ask for another bottle to be produced. It is not acceptable to send the wine back because the taster does not like it. If the wine comes with a screw cap by definition it cannot be corked, but it may have other faults so it is always best the check even if it has been cracked instead of plopped.

Kenya to produce a Premier Cru?

Wine making is as least as old as human civilisation. Wine made from grapes from Vitus vinifera (wine-bearing) species are generally agreed to originate from what is now Georgia about 3,000 BC. The Ancient Egyptians left detailed accounts of vine growing and wine making, although not much about how their wines tasted. The Romans are credited with the spread of Vitus vinifera through Europe about two-thousand years ago to what are now famous wine regions. Today with the exception of Antarctica vines are grown and wine is made on every continent on earth.

Vines perform best within a band of latitudes approximately between 30oN 50oN and the mirror image for the southern hemisphere, 30oS 50oS. Look at a map of the world and all the famous wine producing areas fall into these latitudes. The reason is partly climate as to produce grapes suitable for quality wine making it is generally agreed that vines require a period of dormancy. In the appropriate latitudes and the on-set of winter, cooler temperatures encourage the vine to shut down and the sap falls from the plant above ground to the roots. Dormancy protects the plant against frosts and enables the plant to conserve energy in preparation for the next growing season. As temperatures rise with the on-set of spring the plant awakens, the sap rises again and the vine goes into its busy period of sending out shots followed by flowering, budding, and the final result ripe fruit.

In Kenya seasons are more based upon rainfall than temperature. Kenyan farmers do not talk about the winter, but the short-rains or the long-rains. Kenya straddles the equator and with its tropical climate vines can grow all year round. For producing table-grapes this is not necessarily a disadvantage, but for wine making it is none to good. To make good wine, wine makers search for grapes that are small with concentrated flavours. This is why quality wine producers throughout the world tend to constantly thin their grapes by picking and discarding berries to keep yields at relatively low levels and quality high.

Vine growers in Kenya and other tropical countries have developed techniques to cope with unfavourable climatic conditions. To an extent Kenya has advantage in the form of high altitudes. Kenya’s few vineyards are all at altitude mostly in the highlands above about 1,500 metres. This is beneficial as the altitude provides cooler daytime temperatures than the latitude normally would dictate that prevent the grapes becoming burnt or to hot. Even at altitude though, in Kenya temperatures seldom drop low enough and for long enough to encourage the vines to enter dormancy.

To encourage dormancy or at least to restrict the vine from continually fruiting tropical grape producers tend to double prune. This involves pruning right after harvest usually in February and then again in September. Additional fungicide spraying is also deployed mostly to militate against disease that is more likely to develop in the relatively wet and warm conditions found in Kenya. Some wine makers are experimenting with the idea of applying a hormone to the vine to in effect kid the vine into entering dormancy. To waken the vine from this induced dormancy period, grape growers are also experimenting by applying hydrogen cyamide (Prussic acid). An advantage of this application is that as well as wakening the vine it also encourages the uniform setting of fruit. This technique is used fairly extensively for grape production throughout the world particularly in the New World. Uniform fruit setting has a number of advantages not least being that there is more likelihood of achieving uniform ripeness at harvest. This means that mechanised picking can be deployed, which has the advantage of usually being more cost effective than hand-picking, which cannot differentiate between ripe and unripe fruit.

With modern techniques of vine growing, including on the near horizon the possible benefits of genetic modification, could it be that the tropics including Kenya will offer a future of good or even great wine production? Probably not is the answer, but on the other hand some would disagree and argue in depends on the time frame. India for example is storming ahead in terms of vine planting and wine production mostly within its tropical regions feeding the ever-burgeoning demand of its middle classes. Brazil’s tropical regions are also producing more and more wine. It is at least whimsical to consider that perhaps in twenty-years or so a Kenyan wine may bear comparison with a European first-growth cousin. I will keep you posted.