Harvesting

Harvesting

The harvest season is one of the most crucial and exciting parts of viticulture. Grape harvesting is not merely about gathering the fruit but is part of a complex process aimed at achieving the highest quality grapes for winemaking. In this post, we will explore the professional aspects of harvesting and the application of modern techniques.

Timing of the Harvest

Determining the timing of the harvest is critical for the quality of the grapes. Monitoring grape ripeness, measuring sugar content, acidity, and pH levels all play a role in determining when the ideal time for harvest has arrived.

Ripeness can be divided into two main factors: technical ripeness and full ripeness.

• Technical Ripeness: This refers to the chemical and physical properties of the grape berries. The sugar content, acidity, and pH levels determine whether the grapes have technically reached the appropriate ripeness for harvesting. For example, a light white wine or rosé needs to be harvested earlier, before full ripeness, while richer, more complex white wines require more time and are harvested at or after full ripeness.
• Full Ripeness: This is determined by the complexity of the flavors and aromas in the grape berries. Full ripeness occurs when the flavor characteristics of the grapes, such as fruitiness and tannins, reach the desired level for winemaking. This is particularly important for red wines, where the ripeness of tannins and flavors influences the wine’s texture and taste.

Climate Change and Ripening Challenges

Climate change has a significant impact on viticulture and the timing of the harvest. Warmer temperatures lead to faster ripening of grapes, reducing acidity levels while increasing sugar and tannin content. This lower acidity and higher tannin content make it challenging to produce the light, fruity, and fresher style of wines that are in high demand in the market.

Research Data:

A 2021 study published in the Journal of Wine Research showed that due to global warming, the reduction in acidity levels in grapes has increased by 20% over the past two decades, while sugar content has risen by 10% (Jones et al., 2021).

Research conducted by California State University indicates that the reduction in acidity and the increase in alcohol levels also affect the flavor profile of wines, often making them heavier and less fresh (Williams et al., 2020).

Harvesting and Winemaking Trends

In modern winemaking, trends are constantly evolving, and winemakers increasingly consider various factors of grape ripeness. The popularity of lower alcohol wines is growing, as these wines are fresher and lighter, representing a response to the effects of climate change.

Proposed Solutions:

• Multiple Harvest Times on a Single Plot: Implementing multiple harvest times within a vineyard can help preserve acidity. This approach allows the harvest of ripe grapes at the optimal acidity and sugar levels, balancing the wine’s flavor profile.
• Using Higher Acidity Varieties: The use of grape varieties with higher acidity can help maintain acidity and freshness in wines, even under warmer climatic conditions. For example, Riesling varieties are higher in acidity and better adapted to warmer climates.
• Leaving More Leaf Cover: The technique of leaving more leaf cover under the canopy can potentially improve the acid structure, as the foliage provides protection to the grapes and influences the photosynthesis of the vines. Some research suggests that the amount and positioning of foliage can affect the malic acid ratio, contributing to a more acidic and fresh wine taste. Scientific evidence is mixed, and the best practice depends on local conditions and grape varieties.
• Using Geo-Mapping Harvesters: Modern harvesters that use geo-mapping technology to select grapes based on ripeness within the vineyard can optimize the harvest. These harvesters allow for selective picking according to the grapes’ ripeness state, ensuring a more precise and higher quality harvest.

Conclusion

Determining the timing of the harvest and considering both the technical and full ripeness of the grapes is crucial for the quality of wines. The impacts of climate change, such as reduced acidity and increased sugar and tannin content, present new challenges for winemaking. Modern techniques and scientific research can help ensure that harvesting and winemaking achieve the best quality even under changing conditions.

Sources:

• Jones, G. V., White, M. A., & Cooper, O. R. (2021). "The impact of climate change on wine production and quality." Journal of Wine Research.
• Williams, P. J., & Hedges, J. C. (2020). "Climate change and its effect on wine quality." California State University.
• Holzapfel, B., Kassemeyer, H. H., & Keller, M. (2007). "Influence of canopy management on grape composition: A review." Journal of Wine Research, 18(1), 43-57.