Finally, we have reached the end of the winemaking year.
In the vineyard, soil health is a common topic of discussion now that the vines are dormant. This is a great time to dig soil pits and send samples off to discover more about the composition of the soil layers around the root system of the vines.
Soil pH plays a large part in the health of a vineyard as it controls nutrient uptake. Even if the soil contains plenty of a particular nutrient, if soil pH is wrong, that nutrient might not be available in a form that the plant can use. This can lead to micronutrient deficiencies or toxicities. For this reason, it is very important to manage the soil pH.
At the start of November, areas with long growing seasons are still wrapping up harvest, but most wineries in the northern hemisphere have brought their grapes into the winery. An exception to this rule is any fruit being left out for ice wine production.
Ice Wine Production
Grapes destined for ice wine production must hang on the vine until temperatures reach a consistent 20°F/-7°C or below. Only at this point, can the frozen berries be harvested.
November begins with a lot of activity in the winery and ends with everyone taking a collective sigh of relief. The growing season is at an end and most wine production professionals can take a moment to reconnect with their families and friends and take a well-deserved vacation.
In October, most areas of the northern hemisphere are in harvest and going full out!
Many white varieties finish in early October. Although some reds (particularly early-ripening Pinot Noir) may have started harvest in September, generally, October is the month when most red varieties are picked.
In September’s post, we explored the harvest parameters for white grapes. The factors that a winemaker considers when picking red grapes are similar… flavor, acid, sugar, etc. However, there are two key harvest parameters that are more important (and impactful) for reds than whites: tannin ripeness and anthocyanin accumulation (color).
Now that fall has arrived, winemakers turn their attention to the harvest. In most of the northern hemisphere, harvest usually begins by the middle of this month, if not earlier. It is an exciting time. The culmination of all the hard work in the vineyards is realized in the moments the grapes are picked. Vineyard managers can relax now, but the winemaker’s job is just getting started.
August is the calm before the harvest storm. Vegetative growth has slowed considerably and, in some climates, stopped completely due to water stress. The vine now turns its efforts to ripening the fruit that it has developed earlier in the season. Although the berries are close to their final size, the skins will begin to thin, change color, and gain considerably more weight as they fill with sugar produced by the leaves. In climates that experience rain during this period, splitting becomes a risk.
By July, the period of rapid shoot growth is over. The vine has now created all the leaves needed to ripen its fruit. In wet climates, shoot growth may continue but at a much slower pace. In dry climates, shoot growth stops completely. In very dry areas, the tendrils on the shoot can even dry out completely!
June is a time of great change in the vineyard. At the beginning of the month, the vines have short shoots with berries that have just set. By the end of the month, the shoots are almost fully grown and have discernable clusters. This is a period of rapid cell division for the berries. With regard to the clusters, the number of individual cells within each berry increases in preparation for the next phase of cell expansion (to be covered in July) when the final berry size is largely determined.
After frost season, bloom (flowering) is the first real milestone of the vintage. Harvest follows approximately 100 days after this event. Now that the growing season is in full swing, weather has real repercussions for how the vintage shapes up.
Grapevines have what are known as “perfect flowers.” They have both male and female parts; they self-pollinate. This means that they do not need insects such as bees for pollination to occur (as is common in many other fruits), nor is wind necessary (as is common in some tree species).