Hello everyone! Will Thiersch here, assistant winemaker at Ron Rubin Winery taking over this month’s winemaker notes. With Summer officially coming to an end we have fully transitioned into Fall here in Sonoma County. This is notable for us because many of the last few years have seen a very short fall seasons, with very abrupt shifts from Summer heat to the icy cold Winters. October and November have both been very mild, giving us the nice transition from those sweltering summer afternoons we had in harvest to the nice cool and mild fall day, with noon temperatures ranging from 60-70 degrees. In the first couple weeks of November, we were on the receiving end of some rain and even hail here at the winery! This rain is much appreciated as it will recharge the soil in the vineyard after the long growing season.

Estate Vineyard – Winter is officially upon us!


Now that the 2022 vintage is off the vines, fermented and in barrel, we move on the beginning stages of aging our wine or the Élevage as the French would say. The initial stage of barrel aging brings up our first barrel topping session of the season. Topping is the process of us refilling barrels as they slowly start losing some of their wine. You may be asking why do barrels lose some wine and need to be topped? It is a two-pronged problem; first is when we are initially filling barrels with wine, they are dry and tend to soak up some wine into the oak when first filled. Over the first week or so the barrels will soak up some of the wine that was just put into it, creating a little extra space inside the barrel that we need to fill back up. This is only an issue right after the first fill, however. The second reason is evaporation, which is a slow but continuous process that we need to manage throughout the entire aging process. Often called “the angles share” by distillers, lose from evaporation occurs as part of the process of oxygen exchange through the oak staves in the barrel where wine evaporates through the staves as oxygen is slowly introduced in. The rate of this evaporation can be influenced by a few factors like temperature, humidity, elevation and alcohol percentage of the wine. With all this being said, it is our job to limit this evaporation rate and to keep the barrels topped up. Typically, we will perform this topping once a month with November being our first topping session for the 2022 vintage.


Another process that is happening at the moment is the secondary fermentation, or malolactic fermentation of the wines. Wines will typically have fair amount of a certain kind of acid in them called malic acid, which is a strong/tart acid (think of the kind of acid in a green apple). Malolactic fermentation is a process that converts this malic acid to lactic acid, a weaker and softer acid in comparison (found in milk or cheeses). The primary benefit here is to create richer, softer wines and enhance mouthfeel. This process can start any time after primary fermentation and often is kicked off by wine being put into barrel, which makes this prime malolactic fermentation season! This malolactic fermentation creates a little bit of CO2 gas a by-product, which is why we have special fermentation bungs on our barrels to let this gas pass through without popping the bungs off.

Fermentation Bungs for CO2 to pass through


Now that Fall is in full swing and Winter right on the horizon, the vineyard has begun to fall into its seasonal slumber. Just about all the leaves have fallen off the vines at this point and the soil has been getting recharged by nutrients like compose, cover crop and rainwater. Even though the vineyard itself may be shutting down for the season, our vineyard manager Alvaro Zamora has been keeping busy. He is currently out in the vineyard getting some of the vineyard winter pruning done and out of the way before the holiday season.

Alvaro Zamora, Vineyard Manager


On behalf of everyone here at Ron Rubin Winery, we wish everyone a fun and safe holiday season and continued good health!