Thursday, August 19, 2010

Going High-Tech to Produce Better Wines

We have all heard of the use of technology to fine-tune, tweak, or outright modify a wine through the use of reverse osmosis, spin cone columns, and the like to reduce the alcohol level in a finished wine, but that high tech approach is now being used in the vineyard and during the “crush” portion of the winemaking process, hopefully to reduce the need to finagle with the finished wine.

Many wineries currently employ a sorting line, where leaves, loose stems, and miscellaneous debris are removed from the picked grapes before the grapes enter the crusher, either on an actual table or on a conveyor system that carries the clusters from the bins to the crusher.

Beginning with the 2007 vintage, Dominus Winery in the Napa Valley has been using an “air knife” device called Mistral, which acts to create a sharp breeze across the sorting line to separate any dried berries or plant material from the clusters after they have passed through the de-stemmer.

Going even further, and emphasizing Dominus’ “hands-off” approach once the grapes arrive at the winery, they began utilizing an optical sorting system in 2009. The device is a camera-based, high-speed optical sorter that analyzes individual grapes by size, shape, surface texture (smooth versus raisined), and color. This system, in theory, allows the winery to cull any and all berries or foreign material that would not be considered perfect for making wine to Dominus’ high standards. The system, made by the Swiss Corporation Bucher Vaslin Industries, allows the winery to define the parameters of what the system will accept in terms of whole berries versus crushed berries, acceptable color range, and any stems, leaves or debris that may have made it through the de-stemming process.

Electronic noses (or eNoses) are being used to assess grape maturity based on the volatile aromas (and their precursor compounds) given off by the berries. Researchers at Virginia Tech and elsewhere have found that the eNose evaluation of these volatile compounds provided more distinct and accurate predictive data than the typical physical/chemical parameters that are evaluated on the lab bench. Add to that the fact that the eNoses are extremely sensitive, being able to detect chemical scents occurring in concentrations as low as 10 to 6000 nanograms / kilogram of fruit. That is the equivalent of sensing 8 berries in a million tons of fruit.

Finally, sensors created by the Precision Viticulture International LLC (Viticision) are providing vineyard managers and winemakers with un-precedented access to data collected in the vineyard. These sensors, which are slightly smaller than a dime, can collect data on soil temperature, sun exposure, and ripening within individual clusters in the vineyard. The sensors have been in use at Opus One for the past two vintages.

The data collected are used to decide which rows to harvest first, and which need to ripen further. The data are also used to map the trajectory of the sun over the rows in the vineyard, providing data for canopy management and thereby optimizing color and flavor development while preventing sunburn. The data may also be used to modify trellis design to improve the overall quality of the fruit produced in the vineyard.

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