Federico Casassa, Santiago Sari,* Martin Fanzone, and Marcelo Franchetti 
*Centro de Estudios Enológicos, Estación Experimental Mendoza, Instituto Nacional de Tecnología Agropecuaria (EEA Mendoza INTA), San Martín 3853, M5528AHB, Luján de Cuyo, Mendoza, Argentina 5507, Argentina (sari.santiago@inta.gob.ar)

Currently, the three most popular containers for wine aging are made of oak, concrete, and stainless steel. The oxygen permeability of these materials varies, potentially affecting wine phenolic chemistry. Empirical evidence suggests that concrete allows for slow microoxygenation (much like oak), while imparting no flavors of its own (unlike oak), but improving mouthfeel sensations (unlike stainless steel). To these potential advantages there is that of a relative higher thermal inertia when using concrete. Therefore, the aim of the present study was to evaluate the phenolic evolution of Malbec wines during aging in different tank materials. Grapes from Gualtallary in the Uco Valley of Mendoza, Argentina, were made into wine in 100 L tanks following a standard protocol. After malolactic fermentation, the wine obtained was divided into triplicate containers, including concrete eggs (2000 L), one-year-old French oak barrels with medium toast (225 L), and stainless steel tanks (100 L), for six months. Measurement of dissolved oxygen (by bioluminescence) and overall phenolic composition and color parameters were performed at selected sampling points during aging (June, September, and December). Concrete eggs allowed more dissolved oxygen in wines during the length of the study, with levels 2-fold and 3-fold higher than the one-year-old barrels and stainless steel tanks, respectively. This factor imparted a relative effect on phenolic composition, creating a tendency toward more anthocyanins, tannins, and polymeric pigments in wines aged in concrete eggs, without significant differences relative to one-year-old barrels. Additionally, the color parameters were also influenced, with wines aged in concrete eggs showing higher color intensity, h*, and b* and lower L* and a*, relative to the other two aging treatments. These preliminary results are being complemented with the study of individual phenolics and sensory evaluation of wines by a trained panel.

Funding Support: Instituto Nacional de Tecnología Agropecuaria (INTA) and Zorzal Winery, Argentina