Friday, January 22, 2010

A Fun Tool for Plotting Temperatures

Rhys Vineyards has an ultra-cool application for plotting temperatures for different wine growing regions. Here are a few comparisons I've looked at:
  1. High, low and mean for Bordeaux and Napa. Note that one may toggle between the high, low and mean on the top of the plot. Napa on average is hotter. But what real stands out is the high in Napa are much higher than those of Bordeaux, while the lows are lower. It's common for California wineries to mention diurnal temperature swings as a vital factor in the quality of their fruit. But this makes me wonder. Bordeaux produces arguably the greatest wine in the world with a lower Diurnal Flux (see key at the bottom of the link). Maybe large diurnal flux is not a necessary condition for great wine, but is instead necessitated by the higher temperatures in Napa and more generally California.
  2. Salem Oregon resembles Burgundy, while coastal California sites have a drastically different profile. Aside from a slightly larger Diurnal Flux, Salem looks a lot like Burgundy. Lompoc, i.e. Santa Rita Hills, has a comparable Diurnal Flux to Burgundy, but is actually cooler in the summer! Because of the moderating influence of the ocean, though, Lompoc remains relatively warm throughout the year. This creates an interesting dynamic in my mind. The grapes will likely mature later, and the concept of hangtime to reach phenolic maturity appears to be well-founded. But since the temperature remains warm, there's a risk of sugars accumulating to extreme levels. I suspect this might be why Santa Rita Hills Pinots are often quite high in alcohol, but aren't necessarily jammy or simplistic fruit bombs. While stylistic choices obviously play a factor, SRH seems to be a marginal climate where high sugars are perennially a risk due to later maturation of grapes.
  3. There's a big difference between continental weather and coastal weather. Comparing Rhys' Alpine Vineyard in Santa Cruz near the ocean to continental regions such as Burgundy, Bordeaux and Cote Rotie (N. Rhone) highlights some striking season differences. Bordeaux does receive some coastal influence, but seasons are still evident. A Santa Cruz winter, however, is closer to spring for the other three regions. It's almost as if there is no winter. I have no idea how this ultimately affects vine physiology. But it's clear these regions should make drastically different wines given how different the seasons are.
Temperature and weather certainly are only one piece of the puzzle. But it seems clear to me that emulating the Old World should be difficult if not impossible in California. That doesn't mean wines should be unbalanced caricatures. But they should have a different character.


Matt Mauldin said...

Interesting observation about Sta Rita Hills. High alcohol is always associated with warm weather leading up to harvest- there's a lot more than meets the eye when it comes to ripening.

CabFrancoPhile said...

Yeah, looking at just the temperature is a bit reductionist as so many other factors come into the picture (root stocks, fruit load, trellising, vegetative cover, exposure, and so on). Still seems that the French are often rescued by warm sunny Septembers and Octobers, whereas Cali wine gets pushed over the top by the same. I also think the lower latitude (shorter summer days) of CA means later harvests as well, but September and October are precisely when the oceans are warmest!