At Cornerstone Cellars, making wine is an art and science. For over 30 years, we’ve been dedicated to making diverse, small-batch, high-quality wines representing the best of Napa Valley winemaking. And our warm and welcoming Yountville winery is all made possible through our meticulous approach. From start to finish, each wine is made with a delicate purpose to delight those eager to enjoy its flavor and profile.
Are you ready to learn more about how wine is made? We invite you to explore more about vineyard stages and winemaking, as well as vineyard management practices.
Seasonal Vineyard Care & Changes
Pruning and Cover Crop
The sun is starting to peek out after a chilly winter, and the buds are nestled in their vines. During this time, winemakers work with their vineyard managers and turn their attention to the cover crop that best suits that vineyard site. Among the most photogenic of many options, mustard-colored fields provide a lush habitat for insects and form a natural fertilizer to support the vines, which are pruned for the upcoming season.
Budbreak
The beginning of a vintage starts with a budbreak. These pruned canes push out tiny buds that flower and become grape clusters. Although this is such an exciting season for winemakers, it’s an extremely delicate one, as frost and an abundance of rain can cause damage. Those buds lucky enough to make it through the season will begin to ripen over the summer.
Suckering
Once the budbreak is complete, a season of rapid growth occurs. With so much moisture within their vines, our team has to make sure they strike a balance between forming and growing grapes—this process is known as suckering. If too many leaves and canopy overwhelm the fruit, it can block ventilation and introduce mold or mildew which keeps the vines from producing high-quality fruit.
Veraison
With the arrival of mid-summer, comes the veraison season. Green grapes change color and develop a red skin as sugars start to accumulate. This signals to the winemaker that grapes that will eventually be turned into red wine are ripening. Harvest season is on the horizon. This also creates a second opportunity to drop any unevenly ripening clusters.
Harvest Season: Timing and Technique
As harvest quickly approaches, our winemakers sample the grapes, checking for a balance of sugar, acidity, and phenolics. Weather can play a large role in this season, as heat waves or too much rain can delay harvest. When the weather conditions are suitable for picking, our team will begin picking grapes that span anywhere from two to three months, usually conducting multiple passes over the same vineyard over a period of time. Ripened grape clusters are collected by hand and are taken to be prepped for fermentation.
From Grape to Fermentation: The Winemaking Begins
Once the ripe and healthy grapes have been picked, they are taken to the cellar to be sorted, crushed, and fermented. During the sorting process, stems, leaves, and other unnecessary materials (sometimes called MOG or “material other than grape”) are removed from the grapes. After sorting is complete, it’s time for the grapes to be crushed! The grapes are split to release their juice and contact the skin to bring out color and flavor. As the sugars in the juice are exposed, fermentation begins.
Fermentation isn’t possible without yeast. Yeast converts sugar into alcohol and releases aromatic compounds that build the flavor profile of the wine. Two common types of yeast assist with wine fermentation and aging:
- Indigenous yeast: Native and wild, this yeast naturally occurs on the grapes’ skin. Although this yeast gives the wine unique characteristics, using it solely can potentially lead to “stuck fermentation,” where the wine is unable to organically finish fermentation.
- Commercial (cultured) yeast: There are a wide variety of commercial yeasts, and they can give the winemaker more control over the fermentation process.
Regardless of the yeast we choose to use, we pay close attention to the temperature at which the wine is fermenting. Temperature can change the structure of the wine and even change the flavors.
Why Winemaking at Cornerstone Cellars is Unique
From grape to glass, we put excellence first. Every winemaking technique is thoughtfully completed, and every vineyard we partner with is farmed sustainably and often utilizes organic practices. Committed to belief in quality over quantity, we remain a boutique winery, producing limited batches of wines that capture the essence of the region they come from. Every glass of wine you enjoy from Cornerstone Cellars should spark a conversation filled with joy and celebration.
Kari notes, “I am thrilled to be part of the team at Cornerstone Cellars. We are committed to producing great wines from great vineyards, and making the kind of wines that we want to drink.”
Come Visit Us
If you’re ready to experience Cornerstone Cellars, we welcome you to visit us! Book a tasting, and bring family and friends for a delightful introduction to Yountville CA wineries. We’ll tailor your tasting to your needs and interests, and our team will be more than happy to give you additional insight into the Cornerstone Cellars winemaking process. You’ll even have the opportunity to learn more about our wine clubs and the finest wines in our portfolio. Elevate your wine journey today!