How Much Wine Does a One Acre Vineyard Make?
On average, one acre of healthy vines produces 4 tons of grapes. Depending on the canopy management, trellis system, soil healthy, and overall vine health, vineyard yields can be anywhere from 1 ton per acre to 12 tons per acre. One ton can produce 160 gallons of wine, resulting in 65 cases of wine, or 780 bottles. A one-acre vineyard producing the average of 4 tons will yield 640 gallons, 260 cases, or 3120 bottles.
White Wine vs. Red Wine
White wines can be slightly higher, as they are often picked at lower sugar levels. White wines also need less time to develop on the vine because the skins are not used during the winemaking process. Red wines need more time on the vine to help the tannins in the skin and seeds to develop. For these reasons white grape vines can handle about 15% higher yields.
Quality vs. Quantity
Generally speaking, there is an inverse relationship between quality and quantity in wine. The highest quality vineyards have more restricted yields, resulting in more concentrated wines. If a vineyard is producing more than 6 tons per acre, it will be difficult for the vines to produce quality grapes.
Often times, vineyard managers are asked to do a ‘green drop’ were a portion of the grapes are removed before ripening begins. A common metric for this green drop is to reduce the cluster density to a maximum of 2 clusters per shoot, as long as the shoots are 36 inches long. This green drop allows the vines to allocate more energy and resources to a smaller number of clusters.
The Cost of Quantity
Stretching the vines with higher yields also means more required water and fertilizers. The higher yields mean that the vines must disperse the resources which can dilute the flavors in the grapes. With a vine that has too high yields, it will also struggle to ripen the fruit, which can cause multiple problems. The longer grapes sit on the vine, the acidity will drop and sugar levels will stay the same, throwing off the balance of the resulting wine. The longer the grapes take to ripen also puts them at risk of mold and mildew pressure, causing more issues for the winemaking process.
While it is common for high quality vintages to have a longer ‘hang time’ for the grapes, that just means that the weather allowed for the grapes to spend more time on the vine. It is not ideal for the grower to extend the amount of time to ripen, as that will put the quality at risk. Each vineyard has its own sweet spot where the grower can be pleased with both the quality and quantity of the production.
High Yield Vineyards
Vineyards with higher yields are often planted on deeper more fertile soils. Before planting, a site evaluation should be conducted to determine how much production can be attained from the land. The goals of the grower should be clearly defined so the vineyard infrastructure can be planned.
With a more fertile site, the vineyard can be set up to support higher yields, which can be achieved by expanding the canopy. Instead of using the standard bilateral cordons, the vines can double their production by building out a quadrilateral system, but these decisions must be made before planting as the infrastructure for quadrilateral system is more extensive. The site evaluation should not only evaluate soil fertility and growers’ goals, but also the accessibility to water. Attempting to set higher yields without adequate water will result in significant stress on the vineyard with higher disease susceptibility.
External Factors
Weather patterns and overall climate of the region will have a major effect on the yields. In hot and dry climates, as long as there is enough irrigation for the vines, the vineyard can support higher yields, as the moisture and overall disease pressure is lower. Grapes can hang longer on the vine in order to ripen with lower risk. In areas with autumn rains and more humidity, restricting yields is the safest management method. This ensures that the vines will ripen faster and can be picked before any rain or storms ruin the grapes.
Check out our guide on external factors that affect costs here at https://www.cruland.com/cost-to-plant-1-acre-of-grapes.
Conclusion
Yields within a vineyard can be highly variable and should be balanced based on the site characteristics. With each vintage comes different weather patterns and weather challenges. Every grower and vineyard must find the balance between quality and quantity.