We've often talked about night hand-harvesting Pinot Noir but rarely do we discuss the importance of picking under the stars to produce a white wine with a velvety mouthfeel. Grape skins contain phenolics, which may be fine in a red wine, but the harshness they impart is unwelcome in a delicate white wine. The amount of skin phenolics extracted by the juice is determined by two factors: the amount of skin-contact time after destemming and the temperature of the must. The warming climate is promoting earlier budbreak, which then results in an earlier harvest; the likelihood of picking grapes in sweltering heat during the day has become a likely reality.
Manuel Eligio, Cellarmaster, cleaning up after racking wine. All of Navarro's aromatic white wines are fermented and aged sur lie in European oak ovals which have been modified with modern refrigerated cooling. We have thirty-three ovals ranging in size from 300 to 1500 gallons so that the wine from each vineyard site, or sub-block, can be fermented and aged as a separate lot.
Navarro's Hammer Olsen vineyard being harvested at night. We prefer to harvest all our white wine grapes at night. The grape-skins from some varieties are more astringent than others; Pinot Gris skins can contain high amounts of Quercetin, a bitter flavonol.
We began night harvesting almost thirty-five years ago; there was no scientific proof but we, and other young winemakers, were convinced that the wines have better mouthfeel when produced from cold fruit. Then, in 1986, a paper published in the American Journal of Enology and Viticulture showed that skin contacted Mendocino Chardonnay at 28.6°C (83.5°F) produced four times as much bitter flavonoid phenols, like Catechin and Quecitin, than skin contact at 9.7°C (49.5°F). The grapes for this Gris were harvested at night when the temperature was about 50°F. Those same days, the afternoon temperatures exceeded 100°F. The mouthfeel of this wine would have been coarse had we processed hot grapes. After destemming, the must was quickly pressed, the juice chilled and, a few days later, clear juice was racked to an oak oval to ferment and age sur lie for eight months. Gold Medal winner.