from the Corriere Vinicolo
Problems relating to ripening are amongst the greatest worries for wine growers at harvest time, especially if the weather has been unstable and there have been few fine days during summer. Certainly there are some wine regions in Italy that do not have these problems, the South for example, whereas others, such as those in the Northwest and Northeast, suffer greatly due to uncertain ripening times.
Nevertheless it seems that these problems can be resolved. We became aware of this after a walk in some Friulian vineyards with Andrea Valentinuzzi and Stefano Menotti, oenologists from Synthesis, who have applied an extraordinary solution in Italy for the first time: Extenday.
It consists of a reflective cloth, designed and produced in New Zealand by Jonathan Toye, an orchardist, who has patented it mainly for an improvement in fruit quality (colour, taste, sweetness, size, and longer shelf life) and for advanced ripening. It is made from materials that guarantee greater resistance to traffic and are permeable to air and water; the study of its features and the particular configuration of the weave allow the cloth to provide maximum reflective efficiency in the short term and maximum durability in regard to long-term performance. One of the most interesting advantages of the reflective cloth is that it may be used for several consecutive years, maintaining the same results each year and so guaranteeing a recovery of the cost of the investment Extenday is simply laid out between the rows of the vineyards and tensioned with rubber cords that fitted with wire claws and attached to the poles of the vineyard itself: in this way you obtain a floating surface suitable for the passage of vehicles, that allows you to carry out all the agronomic operations normally needed. Its application increases the reflection of a given wavelength, in practice increasing the amount of light and therefore increasing photosynthesis.
In this way, a cloudy day becomes a sunny day, because the reflected light is multiplied by a factor of five, whereas on a sunny day, the amount of light will increase proportionally. The time when the cloth is laid is very important as different results are obtained depending on the growth stage and its time of application; the best time for applying it is immediately after flowering; it is removed at harvest time.
“Guaranteeing sufficient protection from sun scorching – explains Stefano Menotti – the most obvious advantages are an improvement in the illumination conditions of the production area, the reduction of costs needed to maintain the alleyway between the rows and the improvement of the microclimatic conditions of the vineyard that prevent the development of the main diseases.
Exactly because fewer treatments are used, the grapes are healthier; in fact it has been shown that reflected light prevents the formation of oidium and studies are currently underway in Australia on the ability of the cloth to inhibit the development of the botrytis mycelium.
Another advantage is the considerable reduction in erosion caused by particularly violent meteorological events, with an improvement in the management of the water resources of the soil, thanks to the absorption properties of the cloth that filters water at a rate of 6 mm/hour.
The cloth maintains the soil immediately below it at an ideal humidity, eliminating also infective dews and maintaining the grass on “stand-by”. Another curiosity, that remains to be proven, is that using the cloth is able to increase the number of worms in the soil and therefore proportionally increase the production of humus in the adjacent areas (10 cm) below it”.
“These are all observations – explains Andrea Valentinuzzi – that are yet to be proven, in other words they have been noticed with the use of this material that is not yet very widespread in Italian vineyards.
Regarding the products obtained, we have noticed some exceptional results including better size and colour, because it favours cellular expansion and cellular multiplication of the berry with a consequent increase in the weight of the berry and a reduction in harvest costs as a result of the more even ripening of the fruit on the plant. With the same surface area, but with greatly superior ripening conditions, we achieve heavier harvests while maintaining the same number of buds.
From an organoleptic aspect, a larger amount of aroma precursors have been found in the grapes, due to an increase in the carotenoids, characteristic of white grapes; whereas the varieties with red berries have shown an increase in the amount of anthocyanins, the result being tannins that are softer and more mature and suited to the production of red wines that are more elegant and fruity”.
This does not mean – adds Valentinuzzi – that using Extenday will overcome limiting factors of a pedogenetic nature that render some production areas less suitable than others. Extenday works synergistically with the site where it is used. By eliminating the last obstacle to increased productivity, insufficient light in other words, it allows you to obtain better results in terms of productivity and quality. In any case, in almost any pedoclimatic situation, it is possible to modify production and to improve it from average to good quality, simply by increasing the amount of light”. Blind tastings have been carried out on the finished product by a panel of tasters and the final result clearly highlights the significant differences between wine produced from grapes in vineyards with less sun exposure and wine produced from grapes in vineyards that have had the benefit of Extenday. The field trials using Extenday have so far been carried out in some Friulian vineyards, such as in a Tocai vineyard from the Schioppetto estate in 2003 that was compared with the grapes harvested in another vineyard cultivated in the same area and with the same method. “We have achieved – explains Stefano Menotti – significant differences, obtaining greater aromatic intensity, with more persistent aromas and scents, an absence of green notes and a considerable increase in the weight of the bunches.
With the current harvest, further trials are underway with Cabernet Sauvignon and Ribolla Gialla in the Friuli Colli Orientali Doc region and with Friulian Tocai in the Friuli Annia Doc region”.