High Temperature Impact on Vineyards

The 2017 growing season is well underway in the Napa Valley.  We constantly remind ourselves and our vineyard clients that no matter how good you are, or what you think you have control over, Mother Nature is ultimately in charge of our livelihood.  2017 has certainly started out with Mother Nature poking us.  From an early bud break to below average temperatures, unusual spring rain, hail, and now a major heat spike,  we are reminded that we are actually farmers.  Here at CROZE we have received a lot of emails from customers asking about the current high temperatures and the effect on the vineyards.

Temperature is generally the most important aspect of fine wine growing.  The grapevine’s metabolic processes are dependent on specific temperature ranges.  Over the last week, Napa has been unusually hot.  The temperature has soared into the 100’s.  While this is certainly not a normal weather pattern for this part of the year, it is not necessarily harmful to the grapevines.  High temperatures effect vineyards differently depending on when they occur and the stage of vine development.  Currently, we are through with fruit set and are in stage of grape growth where the cells in the berries are dividing and increasing the quantity of cells within the grape.  Excessive heat during this stage of development can reduce cell division and elongation.  This can result in smaller berries and lower vineyard yields.  It is hard to say if this will have an adverse effect on final grape quality, but generally it does not.  In fact, depending on the rest of the growing season, it could have a positive effect and create smaller more intensely flavored berries.  That will greatly depend on Mother Nature’s plan for the rest of our 2017 growing season.

Heat during the period of ripening called “veraison” can impact the fruit by limiting grape pigmentation and sugar accumulation.  This stage of grape development is still a month away right now.  If excessive heat persists into the final stages of ripening and harvest, the fruit can shrivel and dehydrate.  The damage can be extensive or can be limited to just sun exposed clusters and berries.

Fine wine is an agricultural product and we strongly believe that the key to producing great wine starts in the vineyard.  Our team spends an enormous amount of time in our vineyards and partner vineyards in order to create the style of wines that you have come to recognize as CROZE & Smith Wooton.