July 2009
Didn't always live here. Lived in Michigan where people would actually hunt whitetail deer with Uzis. Not full auto of course, but the state is full of them. Been here for over 20 years tho.
The difference between cool and warmer climate wines can be huge or not so big... Read moreDidn't always live here. Lived in Michigan where people would actually hunt whitetail deer with Uzis. Not full auto of course, but the state is full of them. Been here for over 20 years tho.
The difference between cool and warmer climate wines can be huge or not so big depending on what the winemaker elects to do. Sun and heat have slightly different effects. Each grape needs a certain amount of sun, called sun-hours, to go from blossom to berry to ripe berry. The sun is obviously the source of energy for the plant. The leaves capture the sun energy and use that to trigger reactions throughout the plant.
The berry is like a little engine all by itself. It's trying to produce a seed so that the plant can reproduce. The delivery mechanism for all of the various items needed by the plant is water, that comes up from the soil and evaporates from the leaves. So the water delivers various elements to the berry where they get metabolized into various sugars/starches, proteins, etc., but the driving force behind all of this is sunlight.
Heat speeds up the reactions and increases the transpiration rate as well so the plant draws up and also loses more water. Look at your flowers after a few days of heat - they wilt. How does this affect the berries?
Initially, when it is very young, the berry synthesizes most of its sugars itself. It's getting the basic materials like amino acids, phosphates, vitamins, various inorganic elements, etc., delivered by the water and it puts them together into various carbohydrates and acids. In fact the berry is working really hard to synthesize acids up until veraison, which is the French term used to describe the color change that occurs when the berry shifts gears from growing to ripening.
As the berry gets bigger, more of its carbohydrates are delivered by the plant, mostly from the nearby leaves. And at that point, the growth of the shoots slows down so all the carbs can go to the berries rather than new growth. So the berry gets more sugar even tho it's slowing down its own production.
So now we come to the difference between sun and heat. The metabolic rates slow as the temperature drops. So remember that the berry has worked like mad to synthesize a lot of acids in its youth. If we have warm weather, the berry will be taking on more sugars and to our tastes, will be getting sweeter. If the nights are cold however, the metabolism isn't as fast and the berry retains a higher ratio of acid to sugar. For that reason, people are always looking for areas with big temperature swings from day to night, and the best wines usually come from those areas - the desert mountains in Washington, the mountains in CA, the hills in Ribera del Duero, the Rhone, Germany, and elsewhere.
If you don't have those swings in temp and you have unremittingly hot weather, the rest of the grape is still trying to develop at it's regular growth rate so you can end up with a high sugar content in grapes that haven't actually reached full maturity in other respects - e.g. the skins and associated tannins, the seeds, etc. Sugar converts to alcohol so one characteristic of warmer climate wines can be higher alcohol content and/or a sweeter, riper, wine.
So the first thing you get is a difference in texture between a wine from warm vs cool climates. In addition, when a grape like syrah/shiraz is grown in a cool place, you'll typically find a higher apparent acidity to it. Also, the flavor profile differs - at its best, syrah has a distinct note of black pepper and spice that to me, make it a wonderful grape. You almost never get that from syrah that comes from really hot climates.
But winemaking has a lot to do with it as well. Depending on how long you let the grapes hang on the vine, how long you macerate them, the temperature at which you ferment them, and what you do insofar as attenuating the sugar, acidity, or alcohol levels, you can affect a lot of what you got from nature in the first place. (hide)
