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IQ 2017 Trial Feature: Harvesting at Different Phenolic Levels in the Vineyard

February 21, 2017

Wine Business Monthly’s editors believe that trials are the embodiment of a winemaker’s pursuit of quality, and have selected more than 30 trials to feature at this year’s Innovation + Quality conference, a forum for ultra-premium wineries focused on cutting-edge innovations that advance wine quality.

Innovation + Quality (IQ) 2017 will be held at Charles Krug Winery in St. Helena, California on March 2. At the conference winemakers who have conducted new trials will pour their wines so attendees/fellow winemakers can taste the wines and compare the resulting wines from each trial. In the weeks leading up to the show, we'll feature some of the trials being poured.

For more information on Innovation + Quality, including session descriptions, trials being poured and vendors, visit

Harvesting at Different Phenolic Levels in the Vineyard
9:30 a.m. – 10:45 a.m., Booth H

Winery Name: DAOU Vineyards & Winery

Trial Objective: The objective of the trial is to analyze phenolic levels and sensory factors in wine when Adelaida District Cabernet Sauvignon is picked at difference Brix levels.

Trial Description: A block consisting of 2.14 acres of Cabernet Sauvignon Clone 4 on Riparia Gloire rootstock was used for the trial. The density of the block is 6.5 x 3 feet consisting of 2,234 vines per acre. The grapes were sampled twice a week to determine the total anthocyanin levels available. Having observed previously that the phenolic levels tend to follow a bell curve, we wanted to pick the grapes at three different Brix levels—one before the peak phenolic level, one at peak phenolic level and one past the peak phenolic level. The block was harvested by choosing every third row—therefore creating three different picks. The first part of the block was harvested at 26.3° Brix, before the phenolic levels were leveling off. The second part of the block was harvested at 26.6° Brix, when the phenolic levels were flat. The third part of the block was picked at 27.6° Brix, when phenolic levels were starting to drop. The first part of the block reached a peak level of 1,132 total anthocyanins. The second part of the block reached a peak level of 1,133 total anthocyanins and the third part of the block peaked out at 1,133 levels.

Lot 1: Cabernet Sauvignon Part 1—Harvested at 26.3° Brix
Lot 2: Cabernet Sauvignon Part 2—Harvested at 26.6° Brix
Lot 3: Cabernet Sauvignon Part 3—Harvested at 27.6° Brix

Trial Conclusion: While the levels of three picks were similar in terms of total anthocyanin levels, the bound anthocyanin levels were quite different even though all three fermentations received the same treatment. The first part currently stands at 221 bound anthocyanins, the second part currently stands at 222 bound anthocyanins as well, while the third part stands currently at 301 bound anthocyanins—an increase of 36 percent in stable color. The reason probably has to do with the increased level of tannins generated in part three—a peak of 1,489 ppm of tannins versus levels of 1,209 ppm of tannins for part 2 and 1,259 ppm of tannins in part 1. A noticeable increase in puckering was observed in the third pick which would explain the higher tannin extraction and therefore the increased binding of anthocyanin levels. We believe that hanging longer on the vine has dehydrated the grapes and caused more tannins to be generated. This created a better environment to bind more anthocyanin molecules and stabilizing them. ETS Laboratories chemical analysis is shown below: 

About IQ

Innovation + Quality (IQ) 2017 is the third annual forum for ultra-premium wineries focused on cutting-edge innovations that advance wine quality. This day-long event will take place March 2, 2017 at Charles Krug Winery in Napa Valley.

Sessions will be held in the Carriage House and in the newly restored Redwood Cellar Tasting Room and Hospitality Center. A tented area between these two historic buildings will feature winemaker trials tastings, product and technology demonstrations, and exhibitors showcasing the latest innovations in the ultra-premium winemaking, grape growing, packaging and direct-to-consumer sales.

This event is produced by Wine Business Monthly, the leading print publication for the wine industry, in partnership with Napa Valley Vintners and the Napa County Farm Bureau.

Click here to register for IQ

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