January 2002
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The year ahead The first significant stage in the annual cycle of the vine is bud break, followed by flowering, fruit set, veraison and harvest. Bud break is when the shoot tips burst from the buds. They produce small leaves and grow very slowly using carbohydrates stored in the trunk, until the leaves are big enough to create their own carbohydrates through photosynthesis. In the southern hemisphere bud break occurs in September or October depending on the local temperature. Once this starting gun goes off the rest of the cycle follows according to variety and local temperature. Some varieties reach ripeness quickly in cool climates and some such as Mourvedre, require long periods in hot climates. This allows the vineyard owner/producer to mix his cultivars for optimum use of the cellar. The most efficient cellar would be one with only one 10000 litre fermentation tank. In the vineyard you would plant 10 hectares of grapes of 10 different varieties that all ripen in the same climatic conditions conveniently one after the other, allowing the winemaker to make 10 different wines using the same piece of equipment. Unfortunately that does not work in practice. What actually happens is that you need to install a lot of expensive equipment that is idle for 40 weeks of the year, in order to cope with all the grapes arriving at the cellar door at more or less the same time! Most fruit farmers control bud break and in effect control harvest times by the use of chemical hormone sprays that suppress bud break until the convenient moment. This is very useful because you can then plan your cellar based on maximum capacity utilization. You know within a couple of days exactly when any particular block is going to be ripe. Of course this control is not available to the organic farmer. The other useful feature these suppressants is that they ensure that every plant in the block breaks at the same time, thus ensuring that the maximum amount of fruit is ready when that block is picked. It will all ripen at the same time. With organic farming this cannot be ensured.
The only way to do this organically is to cull bunches that are too late, to try to ensure that the deviation form the norm is kept as low as possible. You must decide on a particular day that the grapes that have reached veraison are the ones that are going into the vintage and anything still green is not. You must hope that the bulk of the crop reaches veraison at the same time and then start your selective pruning, otherwise you get too many grapes that are over-ripe at harvest. This year we were undecided as to whether to make any wine at all. We started out thinking that, as the yield was going to be so low, we should just cut all the bunches off as soon as they reached fruit set. Then after doing this in a couple of blocks we realized that we may actually have a reasonable amount of grapes if we left them to grow. It was interesting to see the grapes develop through the various stages.
The young shoots formed after bud break produced small buttons which enlarged and then flowered, followed by fruit set (the formation of the berries). The next stage was veraison when the grapes went from being green and hard to black and started to ripen. We realized that different plants were all at different stages. Even on the same plant bunches were reaching veraison at different times. We had a very wide spread of development which is really no good for the winemaker and would produce very low yields if those outside the narrow standard deviation were pruned off. We put this down to young and organically grown vines. Remember we had cut them all back after the first year's growth, so although the roots were in their second year the shoots were really in their first.
The other thing we noticed was that our grapes were reaching veraison long after other neighbouring vineyards were being harvested. We put this down to our cooler climate up in the mountains and our young vines. By the end of January we were nowhere near picking any of ours, yet our staff were off every day to earn extra money picking at other vineyards in the locality. Our friends and neighbours were having a few problems with the rain. It was an inordinately wet summer. Normally one could guarantee that there would be no significant rainfall from early December to March. Thus, you could ensure that grape sugar levels would only increase, not suddenly decrease, and so harvest could be well planned with efficient use of available labour. It is more cost effective to harvest one hectare per day for ten days running than to harvest ten hectares on one day. It is also very difficult if one day you test for sugar levels in your grapes and they are perfect, you get your picking gang together ready for an early morning start (when it is cool) and then it rains. Rain is quickly absorbed by the roots and goes straight into the grapes diluting the sugars, acids and minerals while increasing the tonnage. Therefore rain is bad at harvest. After rain you must wait for the sugar levels to be restored, and because it is hot respiration is still occurring reducing the concentration of malic acid. Malic acid is at its highest concentration at veraison and decreases through respiration during ripening towards practically zero. Once the level of malic acid reaches near zero the grape is effectively over-ripe. The balance between sugar and acid levels is one of the vital components of quality in grapes, so an unexpected rain storm at the wrong time can throw the whole vintage into jeopardy. It seems to us that growing most of the grapes you make wine with is important, so that you have total control of this vital stage. If you buy in from someone else you never really know if the grapes that arrive at your cellar, that you tested 2 days ago have not been rained on or really are the ones you bought! As with everything there are many ways of getting the grapes from the vine to the cellar. Some people think this is a vital part of quality control and some do not. The method most usually employed is to cut whole bunches off the vine into small baskets that are then tipped into large wooden bins, sometimes plastic lined, that are towed by a tractor up the row. When the bins are full they are driven to the cellar and a fork lift tips them straight into the de-stemmer/crusher. The resulting "must" of broken grapes minus their stems is then pumped into the fermentation tank and the wine making begins. There are variations on this, the main one being to cool the must in a water-jacketed pipe, but most big cellars follow this general practice. The advantage is speed and simplicity. The major disadvantage is that before you pick you must have an available fermentation vessel. If other blocks have been delayed for any reason and you are still in fermentation with them then there is nowhere to put the picked grapes. All they can do is sit in the hot sun. Some of the grape skins may have been damaged in the picking and tipping process and these may be under pressure at the bottom of the bin getting warm and crushed by the ones above them. What happens then is that fermentation may start or they simply cook. Another disadvantage is the lack of opportunity to sort the good from the bad and the ugly. The French name for this is "triage". The bunches are spread onto a slow moving conveyor and the unripe ones, the partially ripe ones, the over ripe ones and the diseased and rotten ones are discarded by hand. Triage in the vineyard is not possible as all your pickers would have to be very well trained and it would take too long. Another disadvantage is there is no opportunity to sort the berries after the de-stemming has been done. No machine in the world will be able to exclude all the stems from the must. If you have ever eaten a ripe wine grape you will notice how incredibly sweet it is. If you have ever eaten a vine leaf you will notice it is not sweet and is in fact bitter. If you have ever eaten a berry stem it is also bitter and tannic. If you have ever eaten the stem of the whole bunch it is really horribly tannic and bitter. If these foreign bodies are going into the fermenter they will affect the taste of the end product. Whole bunch fermentation is practiced in Burgundy but with very ripe carefully selected bunches handled very carefully to avoid harsh tannins being imparted. Pumping warm mash through a pipe may cause damage and fermentation to start even as the mash cools down in the cooler. All pumping of broken grapes in contact with their juice is frowned on by the real purists. The alternative is more hands on, more labour intensive, kinder to the grapes and involves no pumping of the must. It is extensively practiced in the export fruit trade, of which there is one top quality producer in Tulbagh that we know of. The farm is called Uitvlug and has been at the forefront of quality fruit export to Europe for several years. They practice flash cooling of their fruit in small insulated rooms with huge fans and compressors. They can bring down fruit from +14 degrees to -0.5 in a few minutes and hold it there. The incredibly high standard of fruit demanded by UK and European supermarkets means that the fruit is inspected many times from the sorting/packing shed to the dock and on board ship all the way to the shelf. The reason why the packed fruit must be cooled quickly and held at that temperature is so that it will ripen slowly under controlled conditions over the 3 weeks it takes to get to the shelf and be perfect on arrival. The quality control involved in export fruit production is far more intense than that generally practiced in a vineyard. One fruit fly on a pallet of peaches means total rejection of the whole pallet. It occurred to us that the sorting and cooling practices used by this top producer of fruit could be applied to our cellar. You could pick into small crates the size of milk crates which would stack securely and easily on a pallet on the tractor trailer, they could then be moved from the vineyard into a flash cooler and held at 4 degrees C. Then when the cellar is ready they could be tipped from their small crates onto a slow conveyer for bunch sorting and then de-stemmed. Then they could be berry sorted on another conveyor, lifted on a step elevator and crushed straight into the fermenter This all sounded great in theory. Manie, whose idea the whole thing was, was commissioned to put it into practice! What we needed was a piece of hard standing convenient placed near the cellar door to build the flash cooler. The pallets stacked with crates would be fork lifted from the trailer into the cooler, the doors shut and the cooling started. As we are tucked under the high mountains on our East side we get direct morning sun only very late, being in shadow for the early part of the day. We would started picking a couple of hours before first light to get it done in the coolest part of the day. We sat down with Manie to run through the budget for the year. Obviously the cellar construction was the biggest of the items. But there were many tasks still to be done in the vineyard, all of which require money. We really needed more "pomace" mulch. It was doing its job very well, but was breaking down into the ground much quicker than the straw mulch. Because of this it is great as a provision of carboniferous material to improve the soil and hence as a provider of nitrates for the plants, but the weeds would soon push through the protective layer. We also needed to update our compost tea machine. The practice of organic viticulture was becoming more and more accepted, and the science was developing rapidly. As is shown by this article in the mainstream trade magazine Harpers. People like Mike Benton (ex Cape Organic Products and now running his own business Compost Technologies) are pushing on with new ideas and targets. One of the failures of organic farming is the lack of a replacement for the (albeit traditional) Bordeaux mix which is used to prevent fungal attacks. Mike is working on enhanced beneficial microbes to do the job and we are giving him support. These microbes are sensitive to pressure so our "spray over" device needs to be upgraded to a percolator with air injected into the base. Our program of organic fertilization needs to be enhanced to enable targeting of certain areas of the vineyard. Over the 16 ha the soil is variable and there are some patches of the vineyard doing less well than others. In a non organic farm a couple of bags of nitro-phosphate would be chucked on these and they would perk up, but under our regime new techniques need to be developed (by Manie!!). The other major enhancement to the vineyard is required for canopy management. We aim to have a low density of canopy (numbers of actual leaves per sq m of canopy) to numbers of vines. This is to ensure that enough sunlight penetrates the canopy. Vigorous cultivars such as Shiraz and Mourvedre need no encouragement to grow, but they need the space to grow into. If the trellis system is not big enough allow balanced growth then, by constantly trimming the shoots, the canopy becomes denser and denser. In the end it can resemble a thick hedge of leaves. We want to get a balance between the vines desire to send out shoots and grow and our desire to have a well lit canopy. We looked at many methods of achieving this balance. The whole concept of "Sunlight into Wine" is contained in a book by the same name by Richard Smart and Mike Robinson. Many trellis systems are discussed. In the end we decided to extend the trellis poles by some 300mm to allow an extra wire to be added. The alternatives were to drop the cordon wire to the irrigation dripper wire and put the dripper on the ground or to adopt the Scott-Henry system. The Scott-Henry system is complicated and as we were not predicting over-vigor just giving enhanced space for growth was not worth the effort, especially in training ourselves and all the staff in to adopt it. If it is necessary it is possible to convert at a later stage. Dropping the cordon by 300mm was possible on the new blocks, but harvesting, pruning, tying up and general management would be back breaking work at 50cms above the ground. We wanted our staff to be happy to care for the vines. It is after all repetitive and hard work anyway. The other factor is the dripper line may get clogged with small roots etc. So one on Manie's tasks is to fit custom made pole extensions on 10,000 poles this winter. This will add an extra 0.36 sq m of space for each vine to grow into and enable the canopy to achieve the sought after balance mentioned in previous diaries. We also hoped to have the money and time to undergo a program to remove non-indigenous trees from our river banks. This is important for the provision of water in the whole of the Cape and is an ongoing program across much of the uplands, but these trees are not only sucking up vast quantities of water but they are pushing out the indigenous feinbos and are unsightly. It is our aim to have a wine farm as much in balance with the natural surroundings as can be achieved when undertaking mono-cultural farming. So in the first month of the year we set our sights on what can be achieved in the next 12 months. Manie will be busy not only with this but with the numerous problems that will arise as the year unfolds. Good luck to us and in fact to all our readers for the year ahead. May 2002 be all you wish it to be. Copyright © 2000 Tulbagh Solutions. All rights reserved. |
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