Thank you for Darla Hoffmann, Melanie Chang, Michelle Paris, and Kamal Malik for contributing to last week's discussion on Palo Cortado! Geoff also left an important note on the end so be sure to take a peek if you missed it!
This week: Cool Climate Viticulture
Describe methods vineyard managers can use to encourage ripening in cooler climates and growing years.
First choosing the right grapes that can withstand the cooler weather is critical. More whites can handle cooler (and cold) climates than reds. The location is obviously imperative, avoiding low spots where there might be cold pockets, planting in soils that hold heat in at night, not over-cropping and removing before frost hits, using smaller vines will carry less fruit therefore usually ripen earlier. I think most good vineyard managers do a ton of research on the climate before planting and the track record of that site, and putting prevention strategies in place in case of hazardous conditions.
In addition to Darla's excellent response, I would add exposure is vastly important. Planting on South facing slopes to maximize UV gain is critical. Also, planting near bodies of water (rivers,lakes) that act as heat sinks and can moderate cooler night time temperatures will have a profound effect on ripening fruit in cooler climates.
Along those lines, Canopy management is important. Each cluster needs enough leaves to promote photosynthesis needed for ripening, but position and vigor should be thought about so as to not overly shade the grapes in cool climates.
Overall vine health is also important.Vines need optimal amount of light, heat, nutrients and water to grow and ripen, especially in cooler or more marginal areas. For example, excessive water can promote leaf growth rather than fruit ripeness.Conversely, inadequate water would delay ripening as it delays the vines'ability to go through biochemical pathways to reach ripeness. So, the managers would have to consider and manage all these variables as well.
Vertical Shoot Positioning, just to piggyback on Jeremy's response, is commonly used in cool climate viticulture to mitigate risk of fungal disease [better air circulation] as well as to provide greater sunlight exposure to the fruiting zone. Within VSP, shoots are trained in a vertical fashion along guide wires. With proper canopy management, the fruit is healthier and the earlier sun expose during the growing season encourages even ripening within the grape bunches.
Vine training method is also important in terms of achieving optimal ripeness as well as managing yield and disease pressure.
Along with choosing the specific vineyard site and appropriate varietals, comes one of the most important decisions of all: how close to plant the vines/row spacing - both between and within rows. Other important decisions are rootstock selection and trellising techniques.
Also, the practice of fruit thinning aka "green harvesting" (vendange verte in French) originally evolved in high-end estates in cooler growing regions and slowly diffused out to the rest of the grape-growing world. This has been a fairly new phenomenon, developed in the past 30 years or so. If done early enough before veraison, may result in darker, more concentrated and riper wines.