Before getting to the details, let's look at the numbers. 2010 has been a hot and dry summer. To see how hot and dry, let's take a look at weather data for Loudoun County and Charlottesville, two of the biggest grape growing areas in Virginia.
From June 1st through August 13th of 2010 Charlottesville had an average temperature of 79 degrees with an average high temperature of 91 degrees and a total rainfall of 4.61 inches. Loudoun County, on the other hand, had an average temperature of 80 degrees with an average high of 90 degrees and 4.19 inches of rain during the same period.
None of this means much by itself, so, I took a look at the last five year's worth of data during the same period:
| Area/Year | Average Temp | High Temp | Precipitation |
| C-Ville 2010 | 79 | 91 | 4.61 in |
| C-Ville 2009 | 73 | 83 | 8.42 in |
| C-Ville 2008 | 75 | 87 | 5.15 in |
| C-Ville 2007 | 74 | 85 | 6.82 in |
| C-Ville 2006 | 75 | 86 | 11.23 in |
| C-Ville 2005 | 76 | 86 | 7.53 in |
| Loudoun 2010 | 80 | 90 | 4.19 in |
| Loudoun 2009 | 77 | 87 | 4.37 in |
| Loudoun 2008 | 77 | 88 | 2.24 in |
| Loudoun 2007 | 76 | 88 | 1.62 in |
| Loudoun 2006 | 77 | 86 | 9.43 in |
| Loudoun 2005 | 79 | 89 | 5.74 in |
What do the numbers mean? In both areas the temperatures have been significantly higher than in previous years. Not just the high temperature, but the average temperature as well. This accelerates the growth of mature vines, but damages the growth of non-irrigated younger vines. Older vines can reach down deep to collect water, younger vines don't have have the root depth to be able to do that.
To get even more information I talked to Mark Fedor at North Gate Vineyard and Stephen Barnard at Keswick Vineyards. Here is what they had to say, First Mark:
Realizing that a lot can change between now and harvest, how is the crop progressing?
The grape crop at North Gate is doing well this year. The hot, dry weather has had its advantages and disadvantages. The very hot weather tends to suppress fungi and molds that cause downey mildew, powdery mildew and other rots so our sprays in the vineyard have been way down. We've only done about 6 sprays which is much less than in a "normal" growing season. If you ask any vineyard owner who does the hands-on work in the vineyard, spraying is the least favorite task to do! The heat coupled with the very early bud break this year has really increased growth activity of the vines. This environment provides for an increased chance that the acids in the grape will be way out of balance. This is manifested in higher sugars and lower acids in the grapes. We've had just enough rain at the right times here at North Gate so that the vines have never really gone into drought stress which would tend to slow their growth. This has meant some vineyard work to keep the canopies and fruit zones open with just the right amount of hedging, leaf pulling, and fruit thinning. So in general, the grapes here are looking very good, no disease pressures and the sugars and flavors in the grapes are starting to exhibit some nice character.
Are you expecting harvest to come early, if so how soon?
At North Gate, our Viognier looks like it will come in 2-3 weeks early if the present weather pattern holds. Our Petit Verdot is currently about 50-75% through veraison and it is a bit too early to tell how early, if at all, that will come in. The later harvested reds still have a chance to settle into a "normal" harvest schedule depending on the weather over the next 6 weeks or so.
Are there any potential dangers in harvesting too early?
Yes and a lot of that danger is site specific and variety specific. Everyone has experienced hot weather, but different sites have experienced different levels of rainfall. We've had lots of scattered storms this season with some vineyards getting bone dry and some getting consistent rain.. Furthermore, sites that irrigate are in a different situation because the vines are very happy with the water situation while the hot weather has accelerated their growth. We don't irrigate at North Gate, but those who do would have to pay careful attention to try and control vigor and growth in the vines by regulating the water they dose the vines with. Making a quality wine starts in the vineyard and that means that the best grapes are perfectly balanced between sugars, acids, flavors, and supple skin tannins. Any kind of extreme growing environment has the chance of putting the grapes out of balance and thus affecting wine quality. Hot weather can drive up the sugars which means a higher alcohol wine. At the same time, the acids could be very high or too low to balance against the higher alcohol. Early harvested grapes may not have the flavor development and the skin tannins might be harsh. It is my opinion that the less chemistry manipulation you need to do in the winery, the better the wine will be. It is hard to out do mother nature in a great growing season!
Stephen Barnard from Keswick Vineyards on the same questions:
Realizing that a lot can change between now and harvest, how is the crop progressing?
We expect harvest to come in roughly 2 weeks earlier than last year. It will be more critical to pick at the correct time and for us we are paying more attention to the acidity and PH levels as opposed to last year due to the elevated potassium levels. We have had so little rain and the evening temperatures in the evening have been high so harvest will be early.
Are you expecting harvest to come early, if so how soon?
The crop has held up fairly well considering the drought conditions. Berry size is smaller which means less tonnage per acre, and the sugars are high but the fruit is not physiologically ripe, in that the skins and seeds are still green with elevated sugar levels.
Are there any potential dangers in harvesting too early?
Tough question to answer, I think there will be a small window of opportunity in picking, pick too late and your fruit will be high ph and low acid and picking too early might mean green flavors and harsh tannins in the wine. WE will be sorting everything, acidulating like crazy and getting fermentation initiated quickly and done quickly to get them off the skins to manage the tannins.
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