There are few ways to pick grapes for wine.
By hand. This is still commonly practiced through out the world. It is very time consuming and labour intensive. It also keeps the stalk on the grapes although does keep other MOG (matter other than grape) to a minimum.
Vine dried. This is where they snip the bunch off and leave it to dry in the vine, then come and pick it once some of the moisture has dried up. This increases sugars and intensifies flavours. Only really used in certain styles of wine.
Finally the method we use, Machine harvest. This is probably the most common in Australia due to our large vineyards and flat terrain.
This can be done with 3 operators driving 1 Grape Harvester and the others driving tractors towing gondolas.
The harvester is very tall and straddles the row with the tractors driving in row along side. Inside the machine there are special nylon rods that whip side to side shaking the vine vigorously. This creates a whipping motion flicking only the berries from the bunches leaving the stalks behind. These rods also interlace like fingers so branches can easily slide between them, keeping damage to a minimum. Obviously some sticks and leaves get in but they are taken care of later.
Once the berries are whipped from the bunch they fall onto specially designed plates that allow only the posts and trunks of the vines to pass through as it drives along. These plates also divert the berries into conveyors each side of vines carrying the berries up to the top of the machine where they are dumped onto another conveyor. On their way up they pass through the first blower and stick flicker. This is a high powered fan and grabber spinning so fast it blows everything lighter than grapes out the side. All large sticks and debris are also whipped out the side by the grabber.
Up the top they are dumped onto another conveyor and once again pass through a taller more powerful fan removing leaves that may have been wet. After this the sample is basically only grapes and is dumped onto a final conveyor which sticks out over another row into the 4 ton gondola driving in row beside. On this conveyor there is one final check for metal (staples, screws or bolts) in the sample by a very large magnet which grabs anything that passes. Finally they are in the gondola.
Once full the harvester driver will inform him he can go and unload. He will be closely followed by the other tractor so that stoppage is at a minimum.
Using this method they can either dump straight into the wine crusher or into a semi for transport to other wineries far away.
This method is very effective and can harvest up to 20+ tons an hour.