Follow vines all the way through a vintage as captured in these beautiful photos by Adrian Chitty, A to Z Wineworks’ Artist in Residence, 2019-2021.
Older vines have tap roots that can extend 20 feet into the soil. After harvest, vines pull carbohydrates into the core as deep as possible to weather harsh conditions above the protective soil. What remains visible above the earth is mostly woody tissue.
Once the life-giving nutrients have been pulled into the roots and protected by late January, vineyard teams prune the vines. The two naturally best-placed spurs from last year’s growth are kept for the following year’s canes.
As weather warms (April in Oregon), carbohydrate stores begin to move up from the deep roots into the vine. The small nodes on the canes begin to swell, eventually pushing through new baby leaf growth signaling the start of the growing season.
These nodes formed during last year’s growing season are waiting for their day in the sun. At this stage, they are extremely delicate and vulnerable to damage from strong rains or hail.
Shoot and Leaf Growth
Vine energy is concentrated on developing green foliage that will produce carbohydrates to fuel growth.
The leaves and shoots grow quickly with warmer, longer days. Tendrils begin to form, grabbing at anything to pull the vine towards the sunlight.
Vineyard crews move trellising wires to help tendrils reach for the sky and to keep shoot growth neat, clean, and pointing upward.
Primordial grape clusters start to form during the earliest stage of grape growth.
The tiny caps that have formed on the clusters begin to fall off revealing tiny flowers. The grape cluster is at its most vulnerable during this stage. Wind, hail, rain and frost can irreparably damage the fruit set. This stage can last one to three weeks, depending on the weather. Grapevines are self-pollinating with the help of wind and tiny insects. With optimal weather conditions, all of these flowers will begin to grow as pollinated grapes.
The pollinated grapes have seeds, which will later signal the leaves to send vital sugars into the grape. The grapes that did not pollinate will not receive sugar during veraison.
Over roughly the next 60 days, berries undergo rapid cell division and grow larger. Very little sugar is manufactured during this period but tartaric, malic and other acids develop, while tannins form in the skins and seeds of the young grapes.
For seven to ten days or so, berry growth pauses while the seeds develop. Once the lag phase completes, tannins and acids once again continue to form.
Color begins to show during veraison. Red varieties deepen and begin to turn red, black, gray, or blue, while green grapes soften and start to show more golden colors. Berries double in size and malic acid reduces. Sugars (glucose and fructose) begin to migrate from the leaves into the berries.
As berries continue to darken, skins become thinner and phenolic flavor compounds begin to develop. Clusters are now quite distinct against the green canopy.
In Oregon, long, warm summer days turn to cool nights making for ideal, deeply flavored, berry development. This slow process allows grapes to develop phenolic ripeness along with the sugars. The more developed the phenolics are, the more flavorful and complex the resulting wine will be.
After the grapes are harvested, the vine prepares for dormancy. Leaves change color indicating that the vine is converting the remaining sugars into valuable carbohydrates to be stored in the deep-reaching roots through winter.
Now completely dormant and protected from the harsh winter weather, the vine rests, restoring for the yearly process that will begin anew in the spring.