Why do we sample grapes?

As a part of the assurance of high-quality grapes, it is crucial that the grapes are harvested at the precise moment of ideal ripening. A “ripe” grape ready for harvest is determined by sugar and acidity levels. Desired sugar levels are generally within 19-24 brix; typically, the winemaker will specify the exact sugar levels they are seeking in their winemaking process. 

The Collection



Starting at 8:30am on Tuesday, September 13th, viticulturist Joe Cushman sets out to pull samples from each cultivar that will be harvested for our second year of harvest at Threemile.

These grape samples will be picked up later in the day by fellow Columbia Gorge winemaker Darren Michaels from the Columbia Gorge Winegrowers Association. At Big River Laboratories, Darren Michaels and Kelly Johnson will then crush the collected samples to measure the progress of the contents. The results will indicate the titratable acidity (TA), strength of acidity (PH), and sugar (brix).  



Using separate ziplock bags, 13 cultivars samples will be collected today. For these tests, Darren has requested a multitude of individual grapes be collected from throughout each grape’s respective block.


Joe, walking on foot from blocks A to G, hikes about six miles on a temperate late summer day. With vineyard dogs Salvador and Bean in tow, he cruises between rows, alternating between tasting and collecting grapes from behind protective bird netting. By collecting grapes from various vines throughout each block, an average can be estimated that will reflect the results of the entire block. 


The Results



Thus far, the Albarino from block G and the Mencia from block B appear to be the closest to the upcoming harvest. Roussanne, Merlot, and Syrah are also quickly approaching their time measuring in at 18 brix each. 

 This chart shows test results from the collected samples


Seeing these test results, it becomes evident harvest is just around the corner for some of these cultivars. Joe predicts the first day of harvest to land on September 23rd, starting with the Albarino. 

Going forward, samples will be collected each week to monitor sugar and acidity levels up until every cultivar is harvested. We are projected to harvest a total of 114 tons over the coming weeks at Threemile Vineyard.