Harvest Countdown Begins At Corteau Vineyards

MECHANICSVILLE, Md. — August has arrived at Corteau Vineyards, and around the vineyard, that means one thing: harvest season is getting close.

As the days begin to shorten, our grapes turn from all being green to becoming various shades of purple or gold, depending on the variety.

In the field, our workers remove leaves to make sure the grapes receive plenty of sunlight to ripen. They put up netting to help keep birds, rodents, deer and larger insects out. They weed the worst areas so the tall weeds don’t block the sun or compete for water or nutrients.

In the winery, the winemaker prepares all the harvest equipment to get ready for the season. He fixes, cleans and sanitizes everything that will touch a grape. He orders the yeasts and other additions needed to make great wine.

During all this time, we also test the grapes. About once a week, the crew randomly samples grapes from every variety. Each variety is taken to the laboratory, where we test for sugars, pH and titratable acidity, a measure of tartness.

We then chart these results and compare them with previous years to get an indication of when a particular variety of grapes will be ready to harvest.

These weekly tests continue until all of the grapes have been harvested. For white grapes, we typically harvest in early to mid-September. For red varieties, we typically harvest from late September into late October. The timing varies every year due to rain, sun, heat, humidity and disease pressure.

In addition to lab testing, trained staff taste the grapes and assess the ripeness of the seeds. They taste for flavors that we want in our wines and for the lack of other flavors that disappear as the fruit ripens.

The grapes we harvest are far sweeter than the table grapes typically found in a grocery store. They don’t always look as pretty, but they are riper and grown to give depth of flavor to our finished wines.

During this time, we also monitor for insects and disease. Our current insect issue revolves around the spotted lanternfly, which has recently reached Southern Maryland. These insects love grapevines and suck the sap directly out of the plant. The loss of sap interferes with the plant’s ability to ripen the grapes. It also weakens the vines, making them more prone to die as other threats pile on.

Another big issue in Southern Maryland is downy mildew. When the air outside is so soupy you start sweating the moment you walk outside, the vines are suffering, too. That stagnant air is a playground for mildew to grow and slowly destroy the vines. Breezy air is the antidote, allowing the vines to dry out and helping keep the mildew from spreading.

We also monitor for rain, hurricanes, tropical depressions and other weather events that could adversely affect the grapes. Big rain events can dilute the grapes, but that doesn’t matter so much if we don’t plan on harvesting soon. If we are, we adjust our plans to save the grapes.

Ultimately, the vineyard manager makes the harvest call after consulting with the winemaker and the owner. She is responsible for all the vines and grapes while they are outside. Once they are delivered to the production facility, the winemaker takes over.

People who help us out want to know that on X date we will be harvesting Y grapes.

That’s too easy for agriculture.

Because of all the variability mentioned above, we usually can give ourselves only a day or two of advance notice. At that point, all the staff are notified.

We typically harvest only from dawn until around 10 a.m. because higher daytime temperatures promote grape spoilage. We store the grapes in a large walk-in refrigerator until the entire variety has been harvested. We sometimes take two or three days to get it all, depending on the crew size and field size.

We’ve been known to be outside ahead of a storm, harvesting as much as we can while the wind whips at us from all directions and the sun sets.

It’s not exactly fun, but it is agriculture.

Words can’t readily explain the feeling of getting a harvest in, but these are some that come close: relief, exhaustion, pride.

Learn more about the vineyard and plan your visit at corteauvineyards.com. Corteau Vineyards is located at 38713 Golden Beach Rd., Mechanicsville, MD 20659.

About The BayNet Expert Series

This article is part of The BayNet Expert Series, which highlights local professionals, historians, nonprofits and community leaders who share their knowledge and expertise with Southern Maryland readers.

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