Things to remember: Yield vs. Quality

1.5 Things to remember: Yield vs. Quality

There is a prevailing notion in the wine industry — one held worldwide — that grape yield and wine quality are inversely related, i.e., when grape yield is increased above a certain ‘optimum’, quality begins to decline.

It is thought that as a vine bears more fruit, the intensity of that fruit is diluted, varietal character is diminished, and wine character suffers.

The most common ways of increasing yield are:

• leaving more buds on the vine at pruning;
• fertilizing to correct nutrient deficiencies;
• providing more water to the vine through irrigation;
• changing pruning and trellis techniques.

These operations can affect a vine’s performance dramatically. One effect of each is to increase the vegetative capacity of the vine. This in turn can increase shade within the vine canopy and competition between fruit and vegetative growth, which may inhibit ripening.

Increased malic acid, potassium, and pH in grapes are also associated with shade, as are diminished color and Brix.

Irrigation often increases berry size, which can have a negative effect on phenols and aromatic compounds.

Many of these problems in grapes will be present in the resulting wines.