Our Easter Freeze event, four days of sub-freezing weather this past April, has left us with a season's worth of headaches and can possibly stretch into next year.
These photos illustrate one of the ongoing problems, and that is the uneven development of the fruit. The top photo shows a cluster just entering a stage known as "bloom." Note the tiny flower petals around some of the incipient berries. The bottom photo shows a much more mature grape cluster, with the berries starting to swell. These clusters are on the same Vidal vine, and they're hanging only a few inches apart. The bottom cluster will likely reach peak ripeness at least one week before the top cluster.
This poses a problem at harvest. In commercial vineyards it is most economical to harvest at one time. If you hire a crew of temporary workers, you want to be able to do it all in one pass...you don't want to make a second pass one week later. If you use a mechanical harvester, you have no option but to harvest all at once. With variation in maturity of these clusters, it will be hard to keep all of the fruit on an already-reduced crop.
I've been taking a course at the ICCVE, and they have been stressing the dilemma that large growers face due to this year's freeze: do you drop all the unripe fruit and harvest just the ripe fruit? Do you make several passes through the vineyard? Or do you just leave the fruit for the birds when the costs of harvesting and caring for an uneven crop become greater than any revenue to be gained by selling what is already a small crop to begin with?
I have a small vineyard, so I can make several passes to harvest and crush only the ripe grapes. In Germany, it is standard practice to hand-harvest the steep Rhineland vineyards, in some extreme cases making a dozen passes down the same row to harvest grapes at different stages of ripeness for separate vinification. In this way one single vineyard can produce a broad array of Rieslings, each with distinct qualities. But this is expensive and tedious.
In a perfect year, the vineyard would be managed and maintained so that all of the fruit ripens evenly. Weak shoots and clusters would be removed, trellises would be uniformly maintained, irrigation and fertilizer standardized for each vine. But this year, with many primary buds being killed and thus secondary and tertiary buds sending out shoots a week or two behind the surving primaries, we'll have a grab bag of levels of ripeness at the end of the year.