Throughout the year, we ask winemakers to explain what’s happening behind the scenes each month of the vintner’s calendar as part of our The Vintner’s Calendar series.


April – Topping Up

Sebastiani Winery in Sonoma, California has historic wood carvings on display on their property, including an intricate depiction of the winemaking calendar. Each month is represented separately with a special part of the process a winery participates in to yield great wine. For April, the calendar highlights the process of “topping up.”

Topping up is the process of adding more volume to a batch of wine as to fill any void space that may exist in the wine’s container while it is in bulk. Because oak barrels are porous, wine evaporates; this evaporation is also called the “angel share,” and leaves room in the barrel.

“We want to frequently top-up each barrel because we want minimal oxygen contact with the wine,” explains winemaker Alicia Sylvester. “If there is headspace in the barrel then the oxygen filling that headspace can age the wine at a quicker rate or cause the wine to spoil, turning into vinegar.”

Alicia, who served as Assistant Winemaker at Lancaster Estate before recently being promoted to Winemaker at Merus, mentions that the process can differ from winery to winery. Lancaster Estate, for example, gently stirs the wine in a tactic known as bâtonnage that agitates the lees.

“This method of suir lees again with bâtonnage is the natural way to enhance body and mouthfeel of a wine,” says Alicia. “We hand top all of our barrels to ensure it is treated gently and not pupped though an air pump.”

While topping off may be featured during the month of April on Sebastiani’s winemaking calendar, the process is not soley for this time of year – many winemakers will check their barrels and top off anywhere from every couple of days to every few weeks. Environmental factors such as temperature, relative humidity, the movement of air in the barrel room, and integrity of the barrel will determine how much evaporation happens (and how quickly).

Wine Spectator’s Dr. Vinifera reports that up to 5% of a wine’s production can disappear into the air. “That can add up to a lot of potential sales that the angels enjoy.”


Catch up on the other installments of “The Vintner’s Calendar” here.

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