Second article in the series–The Seasons of Winemaking.

Summer is a crucial season for winemaking, as it is the time when the vines grow rapidly and the grapes start to ripen. In this article, we will explore what happens in the vineyard in summer, and how viticulturists and winemakers can ensure the best quality of the grapes and the wine.

The Vine Growth Cycle in Summer

The vine growth cycle in summer can be divided into three main stages: flowering, fruit set, and veraison.

– Flowering: This is when the tiny buds on the vine burst into clusters of flowers, usually in late spring or early summer. The flowers are self-pollinating, meaning they do not need insects or wind to fertilize them. However, the weather can have a significant impact on the flowering process. If it is too cold, rainy, or windy, the flowers may not pollinate properly, resulting in fewer or smaller berries. This is called coulure or shatter. On the other hand, if it is too hot or dry, the flowers may dry out and fall off, resulting in no berries at all. This is called millerandage or shot berries. Ideally, the weather should be warm, sunny, and calm during the flowering period, which lasts for about 10 days.

– Fruit set: This is when the fertilized flowers develop into tiny green berries, usually in early or mid-summer. The berries are hard, sour, and high in acidity and tannins. They are also vulnerable to diseases and pests, such as powdery mildew, botrytis, birds, and insects. Viticulturists need to monitor the health of the vines and the grapes, and apply treatments or protections as needed. They may also thin out some of the clusters or leaves to improve the air circulation and sunlight exposure of the grapes, and to balance the yield and the quality of the wine. This is called green harvesting or crop thinning.

– Veraison: This is when the grapes change color and start to ripen, usually in late summer or early fall. The color change depends on the grape variety, from green to yellow for white grapes, and from green to red or purple for black grapes. The ripening process involves a series of chemical changes in the grapes, such as the accumulation of sugars, the reduction of acidity, the development of aromas and flavors, and the softening of the skins and seeds. The ripening rate and duration vary depending on the grape variety, the climate, and the terroir. Viticulturists need to measure the sugar level, the acidity level, and the phenolic maturity of the grapes, and decide when to harvest them. This is called picking decision or harvest date.

Previous article: Winemaking in Spring: From Bud Break to Flowering

The Winemaking Practices in Summer

The winemaking practices in summer are mainly focused on managing the vineyard and preparing for the harvest. Here are some of the common practices that viticulturists and winemakers may perform in summer:

– Canopy management: This is the manipulation of the vine leaves, shoots, and branches to optimize the microclimate of the grapes. Canopy management can affect the photosynthesis, the respiration, the transpiration, and the shading of the grapes, which in turn can affect their ripening, their quality, and their susceptibility to diseases and pests. Some of the canopy management techniques include pruning, trellising, hedging, leaf removal, shoot positioning, and cluster thinning.

– Irrigation: This is the application of water to the vines to supplement the natural rainfall and soil moisture. Irrigation can influence the vine growth, the grape yield, and the grape quality. Irrigation can be done by different methods, such as drip irrigation, sprinkler irrigation, or flood irrigation. Irrigation can be scheduled by different criteria, such as soil moisture, vine water status, or climate data. Irrigation can be beneficial or detrimental to the vines and the grapes, depending on the timing, the frequency, and the amount of water applied.

– Fertilization: This is the addition of nutrients to the soil or the vines to enhance their growth and productivity. Fertilization can affect the vine vigor, the grape yield, and the grape quality. Fertilization can be done by different sources, such as organic fertilizers, synthetic fertilizers, or compost. Fertilization can be applied by different methods, such as soil application, foliar application, or fertigation. Fertilization can be beneficial or detrimental to the vines and the grapes, depending on the type, the rate, and the timing of the nutrients applied.

– Pest and disease control: This is the prevention and treatment of the biotic and abiotic factors that can harm the vines and the grapes. Pest and disease control can affect the vine health, the grape yield, and the grape quality. Pest and disease control can be done by different strategies, such as cultural practices, biological control, chemical control, or integrated pest management. Pest and disease control can be beneficial or detrimental to the vines and the grapes, depending on the target, the efficacy, and the side effects of the control measures.

– Harvest preparation: This is the planning and organization of the activities and resources needed for the harvest. Harvest preparation can affect the efficiency, the cost, and the quality of the harvest. Harvest preparation can involve different aspects, such as picking decision, harvesting method, harvesting equipment, harvesting team, harvesting logistics, and harvesting hygiene.

Summer is a busy and important season for winemaking, as it is the time when the vines and the grapes undergo significant changes and challenges. Viticulturists and winemakers need to monitor and manage the vineyard carefully and skillfully, and to prepare for the harvest efficiently and effectively, to ensure the best results for the wine. In the next article, we will explore what happens in the winery in fall, and how viticulturists and winemakers can transform the grapes into wine. Cheers 🍷