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June 2017 WINES&VINES 51 PRACTICAL WINERY & VINEYARD GRAPEGROWING tru - /tan aqueous tannins are a unique blends of ellagitannin and gallotannin that are entirely oak derived and retain all of the aromatic freshness and potency of stave quality oak while maximizing ease of application. Glenn Jeffries | 707.259.4988 www.oaksolutionsgroup.com aquadolce was developed to retain the maximum amount of confectionery oak compounds, which offer aromatic richness and a softer, rounder, more elegant experience on the palate. aquatexture helps balance the fruit and structure of wines, bringing just the right amount of barrel aromatics, toast, roundness, complexity and structure when used during aging or finishing. AQUEOUS TANNINS by tru/tan Vine vigor was measured through multiple parameters (see table "Shoot Vigor and Vine Size") and included shoot length (mea- sured at harvest), number of lat- eral leaves per shoot and pruning weights. A new way to capture vine vigor (called percentage of weak canes) was developed by determining the proportion of canes with less than five nodes. Vine vigor between the ET 100 and ET 70 regimens was not sta- tistically different. However, the ET 25 treatment resulted in very weak vines and had the lowest pruning weights, shortest shoots with few laterals and the great- est percentage of weak canes of all four treatments. These vines also showed leaf yellowing and some leaf abscission. Treatment carryover effects on shoot vigor in the following year were observed in the ET 25 vines, which had shorter inter- nodes and fewer main and lat- eral leaf numbers at fruit set, even though all the deficit irriga- tion treatments received the same amount of water before fruit set and abundant amounts after harvest. The decreased berry number per cluster in the second and third years of the ET 25 treatment suggests that the severe deficit limited flower clus- ter formation in the buds. Similar carryover effects in reduced vine capacity and yield were observed in a long-term trial in Argentina with Malbec. 11 Canopy microclimate To understand treatment differ- ences in canopy microclimate, small sensors called iButtons were used to log temperatures at 10-minute intervals. The iButtons were placed on the exterior and interior faces of grape clusters (see photo of iButton in grape cluster on page 49). Daytime tem- peratures of sun-exposed clusters were often around 20° F warmer than ambient air temperatures; however, at night these same clus- ters were only a few degrees below the ambient air tempera- ture (see "Exterior and Interior Cluster Temperatures," below). While temperatures of the few shaded clusters did not differ between irrigation amounts, the sun-exposed clusters of the ET 25 vines (the warmest of the four treatments) were almost 10º F warmer during midday than those of the ET 100 vines. The smaller and more open canopy and small number of lateral leaves in the ET 25 vines allowed more light and resulted in higher temperatures in the fruit zone compared to other treatments. The ET 25 clusters experienced al- most twice the number of hours above 95° F and fewer hours below 68° F compared to clusters in the ET 100 treatment. Berry dilution? The ET 25 treatment resulted in the lowest yield, smallest berries and smallest number of berries per cluster (see table "Yield and Yield Components"). Although berry weight was smaller in the ET25/100 treatment than fruit in the ET 70 and ET 100 treatments, INTERIOR AND EXTERIOR CLUSTER TEMPERATURES Ambient temperature and simulated cluster temperatures are depicted one week after véraison of Cabernet Sauvignon vines irrigated at various fractions of crop evapotranspiration (denoted by subscripts of ETc) in 2011. Each line represents the average of eight iButtons placed on both the exterior and interior faces of different clusters and logging temperature at 10-minute intervals. The ambient temperature was logged hourly by an on-site weather station. Temperature (˚F) 122 104 86 68 50 32 245 246 247 248 249 2 5 0 Day of the year Ambient ET 25 ET 100 Exterior Exterior Interior Interior