Mother Nature messing with El Dorado County grape harvest

By John Smith

The weather for growing grapes in Fair Play is generally favorable, but there have been exceptions. 1995, 1998, 2005 and now 2010 stand out over the past 21 years here as less than ideal.

In both this year and 1998, the culprit has been El Niño, the Pacific Ocean weather pattern that brings us more rain and cooler summer temperatures. In 1998, it rained through the first week in June, and shoots that should have been 3-feet long by then were barely 3 inches. This year, in addition to the rainy spring, we had lots of sunshine, and the growth of the vines was near normal.

The grapes, however, are not so easily fooled. The time for harvest can generally be predicted by adding up the “degree days” for the growing year (technically from April 1 through Oct. 1, but by the time August is over, we pretty much know what’s in store for harvest).

A professor at UC Davis developed a system of “regions” for California, based on the calculation: take the average temperature for each day in the date range, subtract 50, and add them up. The regions are:

· 2,500 degree days or less: Region I

· 2,501-3,000 degree days: Region II

· 3,001-3,500 degree days: Region III

· 3,501-4,000 degree days: Region IV

· Greater than 4,000 degree days: Region V

Most of Fair Play is considered to be Region II (the same at Rutherford or Oakville in Napa), but this year would have been an almost ideal Region I, and if anyone had planted Riesling or Pinot Noir, it would have been a perfect year.

For Zinfandel, Cabernet and even Syrah, though, it has been much cooler than we’d like.

Many growers had the foresight when the cool weather was evident to reduce the crop load and spread the available sugar over a small number of clusters; others will simply have to wait much longer for the crop to ripen. Will it be late September, October, or even later? The answer depends on the temperatures we see from here on out.

In 1998, the harvest at Oakstone Winery for Cabernet Sauvignon and Merlot was delayed until late October, after an “Indian summer” brought two weeks of warm weather and finally produced grapes of very good quality.

Not to worry, though, each El Niño is usually followed by La Niña, and 1999 was one of the finest years for growing grapes here in Fair Play that anyone can remember.

We all appreciate your good thoughts and prayers for relief this year; and if not, we can all hope for a truly fabulous vintage in 2011.

John Smith works for Oakstone Winery in Fair Play.