PT - JOURNAL ARTICLE AU - Armin Hermann TI - Icewine Authentication by Stable Oxygen Isotope (δ<sup>18</sup>O) Measurements AID - 10.5344/ajev.2014.13143 DP - 2014 Jun 19 TA - American Journal of Enology and Viticulture PG - ajev.2014.13143 4099 - http://www.ajevonline.org/content/early/2014/06/13/ajev.2014.13143.short 4100 - http://www.ajevonline.org/content/early/2014/06/13/ajev.2014.13143.full AB - A partial or even a complete substitution of ice wines by some other wines, though of high quality but harvested under non-ice wine conditions, has to be anticipated in vintages of unfavorable mild winters. Although stable isotopes are known to reflect incomplete phase transitions and are therefore potentially well suited for ice wine authentication, this technique has not yet been applied as an analytical tool against ice wine frauds. As a first approach, this study shows, that ice wine authentication is best achieved by measuring the difference of δ18O-values between the water of ice wine musts and the remaining water in their grape marcs. A positive difference will indicate a fraud. Furthermore this difference was found to be related to the increase of the sugar content in the must due to cryoconcentration. Hence, this difference allows estimating the extent of the cryo-enrichment too. By measuring 47 commercially produced ice wine musts and their corresponding grape marcs, an average difference of about 1.7 ‰ was observed in vintage 2012 in Germany. This difference corresponds to an average cryo-enrichment of about 150% (i.e. an increase of the initial must weight by a factor of 1.5).