The stages of grape growth are filled with lots of complicated terms. One of these terms is véraison.
What Does véraison Mean in Grape Growth?
The process of grapes transforming from fertilized flowers to ripe produce is a complicated physical and chemical procedure.
In short, véraison marks the start of the ripening process. Véraison is a French word meaning the onset of ripening.
Thousands of genes being expressed trigger the ripening process. During this time, the grapes change from hard, bitter green little grapes to aromatic, sweet yet acidic grapes with a beautiful purple or light green color.
Véraison usually starts in July if the weather is not too bad. However, vintage or red grapes won’t change colors until August if the weather is cooler. Typically, the harvest starts 6 weeks after the grapes change color.
Nevertheless, in difficult climates, véraison can take longer to start in vintage grapes and may even cause unevenly ripe grapes.
What’s the Life Cycle of a Grape Vine?
There are 3 stages of grape growth. During phase 1, cell division occurs.
The grapes cells rapidly divide, which causes tartaric and malic acids to build up. At this stage, the grapes will be half their weight and size.
During stage 2, the grape’s growth plateaus. The primary goal is for the seed to grow.
Chemical signaling also occurs, which softens up the grape and gets it ready for the expansion that happens in the next phase.
The second phase can be long or short based on the type of grape. If the grapes take longer to come out of stage 2, they will take longer to ripen. However, if the grapes complete phase 2 in a shorter time, they will ripen faster.
During phase 3, véraison occurs. During this phase, cells within the grapes expand. The cells move from photosynthetic action to heterotrophic metabolic action as the grapes start to change colors.
To put it simply, these changes prepare the grapes for everything that is about to happen. Sugars will accumulate, the grape’s pH will increase, and proteins, tannins, and anthocyanins will also develop.
The flavor and the aroma of the grape become more pronounced. The changes that occur during véraison will drastically affect the quality and profile of the grape when it is harvested.
Why Even véraison Is Important in Winemaking?
Ideally, winemakers want grapes to complete the véraison relatively quickly. Even coloring will create even flavors when the grapes are harvested. This is the secret to making a smooth, balanced wine.
If the grapes are unevenly ripe, the finished wine will reflect it. The wine may have too much alcohol or be too dry, hot, or fruity. This is why evenly colored grapes are so important, as they create the ideal wine.
When véraison begins, the grape fine moves its stored energy from its roots to the grapes. The chlorophyll decrease, and anthocyanins in red grapes increase. Carotenoids will develop in white grapes.
Post véraison, the grapes start to increase in size and weight drastically due to the increase in sugar. The aroma profile also starts to develop. The acidity levels will decrease as the sugar levels increase, creating the perfect balance of flavor.
If the vineyards are in a cooler region, the winemaker can prune the bunches from the wine. This ensured the rest of the bunches on the vine got enough exposure to nutrients and sugars from the roots’ stores.
In contrast, if the vineyard is in a warmer color, some winemakers may prune the leaves off the vine. This decreases the rate of véraison and limits the accumulation of sugars. The ripening phase will be delayed until the temperature cools down.
Véraison is important for winemakers because it determines how they care for their grapes. Each environment will require tweaking to ensure the grapes ripen the right way. For example, vineyards with threats like birds or insects cover their produce with nests so pests cannot eat them.
Why Do Grapes Ripen Unevenly?
Some varietals are predisposed to uneven ripening. There will be perfectly ripe grapes and green grapes on the same vine.
Extreme cases of unevenly ripe grapes are known as millerandage. While this may produce wines that have a sweet aroma, the flavor is anything but sweet. It has an unbalanced green flavor that is unappealing.
Sangiovese, Gewürztraminer, Zinfindel, Pinot Noir, and Malbac, grapes are predisposed to uneven ripening.
Véraison is the start of the ripening phase. It is extremely important to winemakers. What happens during véraison stays in the final wine, so ensuring the grapes ripen evenly will create the best wine.