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44 WINES&VINES February 2017 WINEMAKING PRACTICAL WINERY & VINEYARD Oak toasting method: concept of molecular cooking The patented Vicard toasting system has a steam chamber to bend the staves into a barrel shape in four minutes without changing the chemical composi- tion of the staves, plus a sepa- rate closed, radiant-heat toasting chamber controlled by computer to within +/- 3° C. An infra-red probe measures the temperature on the inside of the barrel during toasting (see "Innovative Tools for Stave Selection and Toasting" in the February 2016 issue of Wines & Vines). In addition to its precision and total reproducibility, this technology made it possible to develop innovative toasting pro- files including gradual toasting, in which the temperature is g r a d u a l l y i n c r e a s e d i n f o u r stages. This unique profile mod- ulates the temperatures that affect the formation, develop- ment and degradation of vari- ous aromatic compounds in the oak. All barrels used for both vin- tages in this research had ex- actly the same toasting profile (gradual toasting). Chemical and sensory analysis of the wines The major aromatic compounds extracted from oak in each type of barrel used in both trials were as- sayed by stir bar absorption extrac- tion/gas chromatography/mass spectrometry and liquid chroma- tography/mass spectrometry. The château's technical person- nel conducted a blind sensory analysis of the 2014 vintage wines. The panel evaluated the following criteria on a six-point scale (from 0 = absent to 5 = maximum inten- sity), with olfactory: overall aro- matic intensity and descriptors related to the contribution of the oak; flavor: balance, tannin quality and length, and an overall quality assessment. Analysis of variance was used to detect any significant differences that emerged from the sensory analysis. Impact of geographic origin, grain and tannin levels on chemical composition of wines For both vintages, when the con- centrations of major oak aromatic compounds found in the wines after élevage were grouped ac- cording to wood origin, no statisti- cally significant difference was A tree growing in a French oak forest is designated for harvest by loggers. OFFICE NATIONAL DES FORÊTS