WINETECH Technical Yearbook 2021

REFERENCES Kennison, K.R., Wilkinson, K.L., Wil­ l iams, H.G. , Smi th, J.H. & Gibberd, M.R., 2007. Smoke-derived taint in wine: Effect of postharvest smoke exposure of grapes on the chemical composition and sensory characteristics of wine. Journal of Agricultural and Food Chemistry 55, 10897- 10901. Ristic, R., Osidacz, P., Pinchbeck, K.A., Hayasaka, Y., Fudge, A.L. & Wilkinson, K.L., 2011. The effect of winemaking techniques on the intensity of smoke taint in wine.

some yeast strains, as well as spontaneous alcoholic fermentations, contained high guaiacol levels. While lower guaiacol levels were found in wines produced with yeast strains UCLM S325, Merit, SIHA A3, AWRI R2, NT 112, RX60, WE 372, VIN 13, NT 202 and FX10. Induction of malolactic fermentation resulted in wines with higher levels of volatile phenols. Production of blanc de noir or rosé wines from red grapes that were exposed to smoke contained lower levels of volatile phenols than red wines produced with the same grapes or juice. Winemakers should consult yeast

suppliers and use yeast strains that produce low guaiacol levels and, if possible, MLF should be avoided in wines produced from smoke-exposed grapes. Wines should be produced for consumption within 12 months after bottling. ACKNOWLEDGEMENTS The authors thank the ARC and Winetech for funding. All the students and interns that assisted with this project are thanked for their technical assistance. Collaborators from Stellenbosch University are thanked for their contributions.

Australian Journal of Grape and Wine Research 17, S29-S40. McKay, M., Bauer, F.F., Panzeri, V., Mokwena, L. & Buica, A., 2019. Profiling potentially smoke tainted red wines: Volatile phenols and aroma attributes. South African Journal of Enology and Viticulture 40, 231-236.

For more information, please contact Heinrich du Plessis at dplessishe@arc.agric.za.

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