Napa Valley vintners have picked up the pace of harvest as lovely weather resumes after bouts of rain doused the valley earlier in the month.  Nice warm days and cool nights are helping to ripen the remaining later varietals and relieve the stress of the inclement weather.

However, high relative humidity and warm weather has lent itself to high disease pressure, and sites with poor drainage or airflow or damage prior to the rain are experiencing degradation from Botrytis and mold.  Winemakers are prioritizing the harvest of grapes that are the ripest or the most susceptible to Botrytis and mold. 

Sites with better drainage and air flow with sound fruit before the rain remain in good shape, and are benefiting from the recent warm days, although harvesting of all but the latest blocks should be on the schedule by now.

For those less fortunate growers, sugar accumulation has stalled and rot is becoming an increasing problem.  At this point, rot could have been mitigated in high pressure sites by sprays, careful leaf removal (damage to grapes during leaf removal may have worsened the problem in some sites), and some growers have used wind machines, leaf blowers, and the fans in sprayers to dry out vineyards after the rains or foggy mornings. 

Despite these efforts, there are a few sites that still have issues, and vineyards with damage need to be harvested before further degradation occurs.  Some growers with issues are making passes to thin damaged fruit before picking, and some are even shaking vines with the hopes that most of the damaged berries will fall off while healthy berries remain.  In some cases, winemakers are slowing down the sorting process to do their best to remove damaged fruit.  The new technology in vineyards is to use an expensive optical sorter (http://blog.vinestowine.com/2010/10/06/vintage-2010-seasonal-update-1062010.aspx) that removes berries that are misshapen or have poor color, and winemakers hope that this technology can be used to remove the random Botrycized berries this year. 

Although it is unusual for Napa Valley to have this type of disease pressure, especially in Cabernet, Bordeaux regularly experiences fall rains and these types of challenges.  We are relying on the experiences of our French colleagues to determine what techniques are appropriate to extract the best out of these grapes, while minimizing the negative impact of rot and underripe characters.  The techniques employed depend on the winemaker preference, the varietal, and the style and price point of the wine.

Techniques on the drawing board include using concentrated wine grape juice to increase sugar content (although an increase in alcohol may lead to more extraction which may not be desirable with less ripe fruit), the use of oak in fermenters or oak fermenters to soften tannin in less ripe fruit, and the use of technology such as reverse osmosis or flash détante.  Shorter macerations, and other less extractive techniques such as lower temperature fermentations and fewer pumpovers are also being considered.

Overall, the vintage is lending itself to lower sugar accumulation, higher acids, and top wines will have ripe flavors with great structure at lower alcohols.  It is important for wine lovers and aficionados to understand that every vintage is unique and special for its own attributes, and hopefully this vintage will be appreciated for California wines made in a more Bordeaux-like style and wine lovers who have long critiqued Napa for making uber-ripe wines will appreciate the 2011 vintage.