From Grape to Glass: An Idaho Vineyard’s Growing Season

Ever wondered how a grape turns into your favorite glass of wine? The journey begins right here in Idaho’s vineyards, where every grapevine goes through an incredible transformation over the course of a year. 

Here in Idaho, the unique climate and landscape play a huge role in shaping the flavors of each wine. From the first sprout of green in spring to the grape harvest in the fall, there’s a whole world of growth happening behind the scenes. Let’s take a closer look at the different stages of grape growing and see how grapes go from vine to wine.

What does a grapevine need to grow?

Did you know that a grapevine can live for more than 60 years? There are some old vines that are at least 90 years old and still producing fruit. Just like any other plant, grapevines go through the process of photosynthesis. In order to complete this process, a grapevine needs warmth and sunlight, carbon dioxide, water, and nutrients. The vines get carbon dioxide from the air, which is absorbed in the leaves. The roots of the vines take in water and nutrients which travel up the vine. 

Weeping

In early spring, when the ground in Idaho warms to at least 50 degrees, the grapevines begin to awaken from their winter slumber. Weeping signals the first visible sign that they're ready to start a new season of growth.

As the soil warms, the vine's roots begin to absorb water. This water mixes with stored carbohydrates and travels up the vine. When the sap reaches the pruning cuts or wounds on the vine, it starts to "weep" or drip out. Weeping indicates that the vine is alive and the internal systems are becoming active again after winter dormancy.

Bud Break

Following the weeping stage comes bud break which typically occurs in late spring. Small, brown and fuzzy buds will begin to form along the arms of the vine. As the temperature continues to warm, the buds will break open to reveal a bright green shoot.

Each green shoot grows rapidly which turns Idaho vineyards into a beautiful, vibrant green color. When there are more leaves present on the vine, the shoots develop faster as they soak up the sun through maximized photosynthesis. 

Bud break is a crucial stage in the growing process and vineyard workers have to remain vigilant. Those first delicate buds are still vulnerable to spring's many unpredictabilities. Idaho is prone to frost during the spring, which can kill new growth entirely. Heavy winds can snap off the shoots of baby buds with ease. Luckily, the installation of weather monitoring devices across Idaho’s three AVAs helps wineries respond proactively to weather changes.

Canopy Management

Once the vines become dense with greenery, Idaho growers will make their way through the vineyards and manage the canopy (leaves and shoots). If there’s too much vegetation, the nutrients from the vine will be more thinly distributed which will cause the wine grapes to lack complexity and concentration of flavor.

In order to optimize the quality and quantity of fruit, growers will implement canopy management techniques such as thinning. By removing excess and weaker shoots from the grapevines, the plants can focus their energy on the stronger, more productive ones. Canopy management takes place during the entire growing season.

Flowering

As spring progresses and the vineyards continue to flourish, the grapevines enter the blooming or flowering stage. Tiny clusters on the shoots begin to open up into green flowers. Each flower cluster has the potential to become a grape, but for that to happen, successful pollination and fertilization are required.

Unlike many flowering plants, grapevines are largely self-pollinating, relying on wind rather than insects to move pollen from one flower to another. Once these flowers lose their caps, small grape clusters will begin to form!

Fruit Set

One of the most highly anticipated stages of the growing cycle is fruit set; when the flowers begin to turn into small, hard, green grapes. With the help of consistent warm temperatures and adequate moisture, they will grow in size and begin to develop their distinct cluster shape. At this point, the berries are high in acidity and low in sugar, and their skins are thick and firm to protect them from pests and diseases.

For Idaho vineyard workers, this stage is all about nurturing the young grapes to ensure a healthy and bountiful harvest. Careful management of the vine canopy to balance sunlight exposure and shade, is essential for ripening. Growers might also thin the grape clusters to reduce overcrowding, ensuring that each grape gets enough sunlight and airflow to prevent mold and mildew.

One Idaho grower mentioned that she checks to make sure the canopy has stopped growing upwards and is putting all its energy into the fruit. One of the signs is drying up tendrils. She said, “If the tendrils do not turn brown and fall away, then the vine is still putting energy towards the canopy versus into the fruit. I manage all of this with irrigation. If the vines still have green tendrils reaching towards the sky, then I know to pull back irrigation.”

Tendrils are long, thin, curly appendages on grapevines that help the plant climb and support itself, rather than crawling on the ground and losing grapes before they ripen. Some say that tendrils are a sign of how plants adapt to their environment and interact with other plants.

Veraison

Veraison, which typically takes place mid to late summer, is the most notable stage of grape ripening, where they undergo a dramatic transformation. For red grape varieties, the berries turn colors from green to red or purple, while white grape varieties shift from bright green to a golden hue.

Ripening

As the grapes begin to ripen, they have high levels of acid and low sugar. The grapes will begin to swell with water and become fleshy to the touch.  At this point the sugar levels increase and signature flavors develop.

Both white and red grapes begin to take on their signature complexities. Red grapes specifically, develop tannins which affect the overall taste of red wine.  Winemakers will begin testing the brix, or sugar level, of the grapes to determine if the fruit is ready to be harvested.

Harvest

Harvest time is the pinnacle, and most celebrated time of the grape-growing season in Idaho.  This is the moment when all the hard work and careful nurturing of the vines leads to the collection of ripe, flavorful grapes. While harvest typically occurs during late summer or early fall, wine grape varietals are harvested at different times depending on the type of grape, elevation at which they are grown, and the style of wine being made.

Once Idaho winemakers determine the grapes are ready to be harvested, it’s all hands on deck! Harvesting can be done by hand-picking or by machine. Hand-picking allows for more selective harvesting whereas machine harvesting can cover larger areas more quickly and is often used when grapes need to be picked rapidly due to weather conditions or other timing constraints. Once harvested, the grapes are quickly transported to the winery to begin the winemaking process!

Dormancy

As the temperatures drop and winter approaches in Idaho, the grapevines enter a state of dormancy, essentially going to sleep to conserve energy and protect themselves from the cold.

The dormancy stage is the final chapter of the grapevine’s annual cycle and is essential for preparing the vines for the next season of growth.

For vineyard workers, dormancy is a time of preparation and maintenance. Vineyard workers carefully prune the vines and the clippings are eventually ground into mulch and recycled back into the earth. 

And there you have it—the grape’s journey from weeping to dormancy! Each stage in the vineyard is like a chapter in a year-long story, filled with growth, change, and a touch of magic. So, the next time you sip on a glass of Idaho wine, remember the incredible journey those grapes took to get there. Cheers to the vines, the growers, the winemakers, and, of course, to enjoying the fruits of their labor!