An impressive group of palates joined the St. Helena Star/Napa Valley Vintners Tasting Panel in May at the Culinary Institute of America at Greystone. Winemakers from Araujo, Silverado Vineyards, Laird, Summers Winery, Honig, Merryvale, Clif Family, Groth, Peju, Clos du Val, St. Supéry, Lang & Reed, Chimney Rock, Dyer Wine, Vineyard 29, Napa Cellars, Folie a Deux, Stags Leap Wine Cellars and Cairdean Estate sat down to review the 2015 vintage of Napa Valley sauvignon blanc.

Anyone thinking that the region’s winemakers are quick to compliment their own wines would be sorely mistaken. This is a group, scalpels ready, who are used to critically dissecting and analyzing their own wines in their labs as they create their masterpieces. (You can almost imagine a succession of “It’s Alive” expressions echoing through the valley at harvest.)

So it was noticeable when, following the tasting of 20 2015 sauvignon blancs, there was general praise from panelists.

Kristin Belair, winemaker at Honig Vineyard & Winery, has been making sauvignon blanc for almost two decades in the valley, and recalled some of the earlier, less-than-stellar vintages she tasted upon starting in the industry. Noting vast improvements over the years, she called the 2015 vintage “really well balanced; a lovely expression of sauvignon blanc with different styles from floral to riper fruits.”

“There is a real diversity of fruit flavors, and the aromatics are fresh,” stated John Skupny, co-owner of Lang & Reed.

Stacia Williams, winemaker at Cairdean Estate, commented on the intensity of floral, fruit and minerality, and sensed that some of the wines were held on the skins.

The term “held on the skins” means that the juice of just-picked grapes stays in contact with the skins for a period of time. Generally, aromatic grapes like sauvignon blanc are put into a press shortly after arriving in the winery cellar, so the juice is released and separated from its skins. The winemaker wants limited contact between the juice and the natural phenols on the skins of grapes because these phenols (which include tannin) can add an astringency or bitterness to the wine. Generally, this is avoided when a fresh fruity wine is desired. Some winemakers, however, allow a very short period of skin contact (just a couple of hours usually) for an added layer of aroma and flavor complexity.

Historically, Napa Valley sauvignon blanc wines have not only had more skin contact, but as Jon Emmerich, winemaker at Silverado Vineyards, noted, “there used to be a lot of sweet sauvignon blancs. With these wines (the 2015 vintage), there is not a lot of residual sugar.”

Residual sugar as well as oak were used to mask the inherent herbal and pungently grassy aromas and flavors of sauvignon blanc that were unpopular in the wines decades ago. With improved vineyard and cellar practices, the floral and fruity nature of the grape can be stressed instead. The wines today that do include a slight touch of sweetness (referred to as off-dry) or oak-influenced flavors, integrate these finishing touches as a part of their desired style.

Not that everyone wants the natural green-ness of sauvignon blanc to be squelched. A touch of fresh cut grass can add to the overall flavors and complexity of the wine, and provide a distinguishing characteristic so sauvignon blancs don’t taste like mass-produced “who cares what the varietal is” wines. As Master Sommelier Bob Bath stated, “I am glad there is an herbaceous grassiness in some of the wines; this is a key part to sauvignon blanc character; it’s important.”

In regard to the varying floral, fruity and herbal flavors the panelists found in the 2015 wines, Sara Fowler, director of winemaking at Peju, spoke to the harvest itself, stating, “production was down 40 percent on average” and likely caused winemakers to get creative in the cellar, possibly blending in other grape varieties to make up for reduced crop.

Tim Carl, winemaker and journalist, discussed another potential cause of the varying flavors: the choice of yeast. This may seem odd to anyone new to winemaking (you mean, there are yeast stores?), but it’s very common. Flavors of sauvignon blanc can be greatly influenced by the choice of yeast strain used to start alcohol fermentation. Where one may bring out the floral aspects of a wine, another can enhance the grape’s natural citrus character. Some winemakers purchase a variety of yeast strains to encourage a range of flavors in the wines.

Curious as to some of the many aromas and flavors found in the 2015 Napa Valley sauvignon blancs? Those are noted below with the panelists’ favorite wines of the tasting:

Honig Vineyard & Winery ($18) having crisp tangerine citrus, sweet banana and ripe cantaloupe melon fruit with a hint of white blossom that finishes just off-dry.

Rombauer Vineyards ($24) shows fresh and zesty orange and lemon citrus with ripe Asian pear flavors.

St. Supéry Estate Vineyards & Winery ($22) is dominated by ripe, juicy pear aromas and flavors.

Three Click Wines ($24) has a refreshing blend of lemon citrus and fresh spring grass.

Varozza Vineyards, St. Helena ($25) has round ripe flavors of sweet banana.

Yao Family Wines ($32) has lemon-lime citrus with fresh lemongrass and refreshing acidity that is rounded out by an off-dry finish.

Catherine Bugue, the Star’s tasting panel columnist, loves writing about — and drinking — wine. You can contact Catherine at catbugue@gmail.com. Only wines from Napa Valley Vintners member wineries are accepted and tasted. Many wineries offer local residents discounts on their wines through the Napa Neighbor program. Visit napavintners.com/programs and click on Napa Neighbor under Community to learn more.