Wine Wednesday: What happens during harvest?

By: Cecily G

Happy #WineWednesday fellow wine-os! Today, we are going to veer slightly away from our weekly Rhône 101 lessons to talk about a topic that is very relevant this time of year: harvest! Don’t worry, we will be back to your regularly scheduled programming in no time. ;) We’re going to go through the what, when, why, where, and how of this exciting and crucial winemaking process!


The harvesting (or “picking”) of grapes for wine is something that happens every year, and is what separates each wine into vintages (the year the wine grapes were harvested, often found on the label of a wine).


In California, wine grapes are generally harvested between August and October, depending on the grape varietal. The exact date of harvest is dependent on sugar, acid, and tannin levels in the grapes, as well as weather. Certain vineyards, blocks, or even rows may be harvested on different days over the course of a harvest season because of these factors. Time of day is important during harvest as well, as too warm temperatures may cause the grapes to prematurely ferment. Picking at night or very early in the morning, when it’s the coolest, is the most optimal time.


Harvest happens once the grapes have completed verasion (the turning of color in the grapes, leading to the maturing of the berries). Grapes are ready to be harvested once the sugars in the berries reach a certain level. Winemakers can taste the grapes to see if the sugars are high enough in the berries for harvesting, or use a tool called a refractometer.