The term is used to describe the matter that winds up mixed in with the grapes during harvesting and must be removed before the fermenting process. Sorry to report this “matter” includes not only twigs, leaves and stems from the vines but also anything else on or near the grapes, including bugs, birds, snakes and mice!
If hand sorted, wine makers can remove up to 99% of the MOG. But with machine harvesting (which is cheaper than using human harvesters) — well, let’s just say it’s fast and less expensive but far from perfect in removing MOG before it, along with the fruit, makes it to the barrel for fermentation. So it seems the old adages remains true — you sometimes get what you pay for … and less ain’t always more!
I have worked sorting tables at Vint Hill Craft Winery in Virginia and Tin Lizzie Wineworks in Maryland. Sorting takes time and increases the cost of producing the wine. One wouldn’t want to remove 99% of the MOG. At Vint Hill we were removing the jacks on the second sorting table. However some did make it past the sorters, which is a good thing. Taste the jacks. They will have flavor and add to the tannins. For a video of a double sorting table check my winemaking site at http://winemaking.winetrailtraveler.com. The video is at the blog for October 28 and 29th.
This is an insightful perspective. FYI, the information came from Lenn Thompson’s blog. Thanks so much for the comment and for providing the winetrailtraveler.com link for JOTT visitors. I will definitely check it out. I hope this generates a great discussion because I’d certainly like to know more!
RT @MikeIsaac: someone taught me the “put a wooden spoon over boiling pot and pasta wont boil over” trick and it is the most life changing… 2 months ago
JoyoftheTable.com® 
I have worked sorting tables at Vint Hill Craft Winery in Virginia and Tin Lizzie Wineworks in Maryland. Sorting takes time and increases the cost of producing the wine. One wouldn’t want to remove 99% of the MOG. At Vint Hill we were removing the jacks on the second sorting table. However some did make it past the sorters, which is a good thing. Taste the jacks. They will have flavor and add to the tannins. For a video of a double sorting table check my winemaking site at http://winemaking.winetrailtraveler.com. The video is at the blog for October 28 and 29th.
Terry,
This is an insightful perspective. FYI, the information came from Lenn Thompson’s blog. Thanks so much for the comment and for providing the winetrailtraveler.com link for JOTT visitors. I will definitely check it out. I hope this generates a great discussion because I’d certainly like to know more!
Ciao,
Tonya