June is when things start happening and the vines start getting busy. New shoots are growing fast. What were once deserted rows of twisted brown and grey wood clinging to wires are now bristling with freshly grown leaves, ready to take in all the sunshine. It is from the sun that the sugar comes and enters into each grape, which will eventually be turned into alcohol.
This also reduces the over-all yield of the vineyard, sometimes by a lot. That’s one of the biggest choices that winemakers and grape growers have to make. For example, reducing the yield by green harvesting to 2 tons per acre means that all that sugar and flavour is going into a very small amount of grapes. That means they will get very concentrated wines but won’t have very much of it to sell. The flip side of that is to try to get a lot of grapes without green harvesting (roughly 6 tons per acre or more). In this situation, the sugars are spread out over more grapes resulting in less concentration and less flavour, but more wine to bottle.
Supply and demand then dictate how much each bottle of wine will cost. That’s why some producers have to charge more because they have less wine and need to make up the costs of producing it. Others can charge less because they have more of it to sell. It’s all a part of the many complicated choices that have to be made by wine producers everywhere.