Dear Growers, Vineyard Owners and Winemakers:Attached please find a document from a comprehensive study conducted by the Australian Wine Research Institute and Australian Department of Agriculture & Food:
http://m.awri.com.au/wp-content/uploads/smoke_effect_in_grapes_and_wine.pdfSo many questions have arisen in relation to the affects of the Rim Fire on our grapes and ultimately on our wine. I found this source to be reliable and informative. It provides practical explanations for what may or may not affect grapes and vines in terms of volume of smoke, timing of smoke exposure and varietal sensitivity to smoke, along with ways of mitigating smoke-taint effect, both in the vineyard and winery.Some key points found in the study:
- “Smoke exposure to grapevines can result in the delay of fruit ripening. “On a number of occasions, studies have shown fruit from smoke exposed vines to have a lower sugar content in comparison to fruit from unsmoked vines.” ***In some vineyards we are currently seeing a decrease in sugar levels.
- Key periods of grapevine sensitivity to smoke exposure and the development of subsequent smoke aromas and compounds in wine: “From 7 days post veraison to harvest, potential for smoke uptake is at its highest.”
- Varietal differences: “Berry skin thickness may also possibly affect smoke uptake and development.”
- Winemaking techniques: “White wines have been found to have less smoke-related sensory and chemical aspects due to a reduced fermentation time on skins in comparison to red wines.”
- Results suggest that a single heavy smoke exposure for 30 mins occurring during a sensitive stage of vine growth (from 7 days post veraison to harvest) was sufficient to create smoke effect in wine.” And “repeated smoke exposures or smoke exposures for a long period of time result in the accumulation of smoke aromas and compounds in the final wine.”It is important to note that grape handling and winemaking techniques can influence the creation of smoke effect in wine. Techniques to reduce smoke effect in grapes and wine are detailed in the attached document. I trust you will find this resource helpful.Regards,Mark SkenfieldVinescapesVineyard Consulting, Development & ManagementP.O. Box 2370Murphys, CA 95247Cell: 209 743 4515