Winter Injury and the Endless Mountains Region
By: Michela Centinari and Denise Gardner
This visit was a great opportunity to see several vineyards in the area and to engage in interesting discussions with local wine grape growers and vineyard managers. I was extremely impressed by the high quality of management being conducted in the vineyards. Jeff Zick, recently hired as vineyard manager at Nimble Hill Winery, is a great addition to the Endless Mountain region grower’s team.
Most of the growers have both French-American hybrids, including cold-hardy varieties (Marquette, Frontenac gris, and Petite Pearl), and vinifera wine grape varieties, including Riesling, Gruner veltliner, Pinot grigio, and Pinot noir.
I also had a chance to evaluate the extent of winter cold injury the grapevines in this region experienced. As expected, the hybrids did not show much or any cold damage symptoms. Varying levels of cold damage were observed in the vinifera varieties. The growers pointed out sections of their vineyards, likely in poorly drained areas, where winter damage was extensive (i.e. near 100% bud mortality). However, other sections of the same vineyard experienced much less cold damage.
Vascular system damage was observed when sectioning canes with alive, but poorly growing shoots.
Unfortunately, those shoots will start to collapse during the summer.
Likely most of the vines have alive and healthy shoots developing on the scion side of the graft union area, which will need to be used to retrain new trunks.
If your vines experienced winter cold injury you can find useful information on how to deal with injured vines in the last issue of Viticulture Notes edited by Tony Wolf. http://www.arec.vaes.vt.edu/alson-h-smith/grapes/viticulture/extension/growers/current_VN_newsletter.pdf
In the winery, we talked about everything from the addition of bentonite during wine production, the use of temperature control during production of aromatic white wines, and defects associated with wine.
It is important to remember that the use of bentonite is related to the protein stability of wines. Adding a “standard addition” of bentonite to your wines does not guarantee protein stability in each wine produced. Additionally, some wines may not require a protein addition. For those wines that do not have protein instability issues, the addition of bentonite can contribute to some aromatic and flavor losses. I was impressed that Kevin, the winemaker at Nimble Hill Vineyard and Winery, has been keeping an accurate record of protein stability and total bentonite additions for each wine produced. This practice should be implemented at every winery if it is not done so already. For more information on protein stability and a brief protocol on protein stability testing, please refer to this document by Bruce Zoecklein.
There was a lot of discussion on aromatic white wine development, and the discussion was led through a tasting of several wines produced in Pennsylvania and throughout the world (benchmark producers). Aromatic white varieties like Riesling, Gewurztraminer, Vidal Blanc and delicate white varieties like Gruner Veltliner, Pinot Gris/Grigio, and unoaked Chardonnay should be refreshing with a bright acidity and fresh, fruity, floral aromas and flavors.
To retain these delicate aromas, it is recommended that wineries
- use temperature control during fermentation.
- limit the wine’s contact with oxygen to avoid oxidation and development of oxidative aromas.
- rack wines off the gross lees quickly after fermentation
- stabilize with sulfur dioxide additions (in temperature control tanks) soon after primary fermentation (if no MLF will occur).
When the tanks are not temperature controlled, warmer ambient temperatures can blow off the aroma and flavor compounds associated with these varieties, in addition to causing stability issues that may lead to the development of off-flavors. For some production addition options during aromatic white wine development, please review this document by Enartis Vinquiry.
Visiting the Endless Mountains region is always a pleasure. The region is quite picturesque, and if you haven’t had the opportunity to visit the region and taste their wines, I strongly recommend it.