How Extreme Heat Affects the Wine You Drink

The hot weather is a great time to enjoy some of the great wines and craft beers being offered by local wineries and breweries from around the world. Sometimes we may wonder how vineyards progress through the seasons and how they arrive at the Harvest in September or October. 

Today, we’ll take a look at what vineyard managers are doing to help protect their crop from this oppressive heat and deliver the best fruit for the upcoming bottling.

Spring is the vine’s first season. Various growth zones will create different months; however, the progression is relatively the same. Wherever the vineyard, the vine is planted when the threat of frost is gone. The destiny of the vine is established during this time. First plantings may create some fruit later in the year but soil and root stock selection is the make or break season for a good fruit producing plant.

The vines endure a lot during their growing seasons and hot weather may require watering. If a vine receives too much water during a rainy spring season, the roots won’t have to work hard, resulting in a weak root system.

There are many things viticulturists will control—weather is not one of them. Adjustments will be made depending on the weather patterns.

Summertime usually brings more stable weather, longer days and sunlight. The vines convert the sunshine into energy through photosynthesis, where the chlorophyll converts carbon dioxide into oxygen.

Vineyard managers also decide how to groom the vines.  The “canopy” or the leaves covering the vine can be cut at different time intervals depending on the amount of sunlight needed on each side of the vine. Depending on the amount and strength of the sun on the grapes, the berry temperatures will fluctuate.  Direct sunlight on the fruit can rob grapes of color and flavor. This is monitored daily and adjustments are made as necessary.

Summer can also be the season when fungal disease and pests descend on the vineyard. You may have seen rose bushes planted among the rows of vines at your favorite winery. Roses are subject to some of the same fungi, and will show them earlier than grapevines. This is nature’s little alarm system. If a fungus hits a vine, it can severely reduce or eliminate fruit production.

During the last days of summer, winemakers make a significant decision that will affect your glass—they may decide to perform a green harvest, removing many grape clusters to direct the full force of the vines energy to the remaining clusters. This is very risky since certain events during the few weeks remaining before harvest can severely affect the production. Droughts can damage the remaining grapes leaving them unbalanced.  But if all goes well, thinning the fruit can deliver an amazing boost of flavor and nutrients to the remaining fruit.

During fall, the harvest is completed with timing being extremely important. Wait too long and the crop may be lost; too early and flavor is not at the optimum level. These are all decision the winemaker and vineyard manager must complete. During winter, the vines fall into dormancy and are at the mercy of the weather. Preliminary pruning can take place at this time.  

The vineyard is always being monitored and improved throughout the year.  Different countries have different months for the seasons depending on where they are located. No matter where the location, two things for excellent wine production is for certain, science and vineyard knowledge is extremely important and none of us can control or predict the weather. The vineyard manager must be diligent and able to make quick decisions to enhance the crop.