~ Stephen Tebb, Winemaker
Halloween has gone by, November’s here and guess what – we’re finally getting the burst of harvest action we’ve been waiting for!
We’ve been in “harvest mode” since September, yet the grapes have not. The growing season started off late due to a cold and wet spring, and then the long, cool summer slowed down fruit development. Just when we were ready to get started with harvest, we received rain at the beginning of October, which didn’t do anybody any favors. So by Halloween, we were only 40% done with harvest.
The vines are beginning to shut down with the cool night-time temperatures, but the grapes are finally nice and ripe and we are bringing them in as fast as we can!
In my previous blog, I took a look at the Science Behind the Art of Winemaking. I would like to continue that theme in discussing how we are processing our fruit during this harvest.
Fortunately, advances in science and technology have greatly improved the wine industry’s equipment for processing grapes, resulting in gentler handling of the fruit and better wine quality.
Typically, we achieve clean fruit in the tank by sorting the grapes by hand. After de-stemming, the berries travel along a vibrating sorting table. We pull out any unwanted leaves, bits of stem, green berries or anything else we don’t want. Our sorting table is in itself a great improvement over previous methods. However, it is a slow, laborious job, yet necessary to ensure that only the best fruit ends up in the fermentation tank.
This year with the delayed harvest, ripening is happening in all the vineyards at once . Considering how much fruit there is to process and how little time we have – along comes automated “optical” sorting to the rescue!
The use of “optical” sorting is one of the latest technological advances to be applied to the wine industry. With this system, we can obtain sorted fruit and ensure our high standard of quality, while doubling the speed with which we could do it by hand.
There are two primary brands of optical sorting units. Both units utilize a specialized “optical eye” digital camera that photographs each row of berries as it passes by on a conveyor. A computer, programmed with software to recognize unwanted berries and other debris, scans each photo in milliseconds and sends the information to a series of air jets located at each berry position on the conveyor. The parameters for scanning can be customized as needed for each batch of grapes.
As the fruit travels along the conveyor at 7 feet per second, the good fruit is sent to a receiving bin. At the same time, any bits of material that the computer has identified as “unwanted” receive a strong pulse of air from above. The pulse forces only the debris down onto a secondary conveyor that carries it away to a separate waste bin.
To get a better understanding of how this works, check out each of these optical sorting units in action on the following YouTube links.
http://www.youtube.com/watch?v=vfHz-ULzlCE&feature=related
http://www.youtube.com/watch?v=teeszu-ugmE&feature=related
After using this type of system a couple of times, we can confirm that the quality of the optically sorted fruit is as good as or better than what we can do by hand, and it’s accomplished twice as fast.
There is no doubt that progress in science and technology has been a major factor in the dramatic improvement in the level of quality and consistency that we enjoy in our wines today and that is for the better. We can especially appreciate this fact when considering the challenges of the 2011 vintage.
It’s time to put this harvest to bed, with a little help from our optical friend!
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