The View from the Vineyard - July 2024

Here in Sonoma County, we are at the cusp of veraison, with all metrics pointing towards a bountiful harvest that tracks along the five-year average. Most of a grapevine’s “big,” landmark moves are temperature dependent: bud break, flowering, fruit set, ripening. This year, spring weather remained favorable for each milestone, with hot June days multiplying our grower degree days into a blinking arrow pointing to another “early” harvest.

is august harvest new normal? (probably so at torrey hill)

Bloom at Torrey Hill Vineyard (male flower parts drop pollen atop female parts)

 

Here is a photo of bloom at the Torrey Hill Vineyard (May 10, 2024). Ideal weather for flowering is like Goldilocks: not too hot; not too cold; dry, sunny, and warm; bonus points for mild breezes. Average daily temps need to reach 68F for about a week to ignite bloom, and Sonoma weather looked textbook.

weather data deep dive - daily highs & lows

Daily highs and lows for weather station 16, Windsor, CA

weather impacts bloom which affects fruit set which informs yield

These 18 days in May provide a good snapshot of weather during bloom. I collected this data set from the weather station closest to Torrey Hill Vineyard, the station I use to track our home ranch. As detailed above, May weather was mild and sunny, exactly what we winegrowers crave. In fact, weather/temperature is the most critical determining factor for successful fruit set. Consider how overcast, cloudy, wet weather inhibits complete fertilization. Sometimes rain prevents the calyptra (cap) from detaching, so the male flowers parts can’t expand properly. Prolonged cold diminishes the pollen viability and results in uneven (& poor) fruit set. “Shatter” occurs when unfertilized berries fall away from the cluster.

shatter (failure of fertilization)

Shatter is easy to identify after fruit set. Give the cluster a gentle tap and dried, brown plant detritus falls right into your hand. Likewise, those teeny green “shot berries” result from pollination without fertilization. Small and seedless, shot berries never develop into grown up wine grapes.

vintage 2024 displays excellent fruit set

Robust set at Nightwing Vineyard, Petaluma Gap (6/28/24)

Luckily, Sonoma sunshine maximized fruit set and minimized shatter. Indeed fruit set looks robust around the county. With fruit set in the rear-view mirror, veriason is the next milestone for our grapevines. And we are at the cusp. (I searched far and wide to find you the first berry of veraison!!).

welcoming veraison

A single red berry marks the start of veraison at Torrey Hill (7/5/24)

The earliest berries turning purple in 2024 are about a week behind 2022, which we all recall being “an early harvest.” While 2024 started out the season BEHIND 2023 for grower degree day accumulation, above average warmth in June (and into July) catapulted us past 2023 metrics, meaning vintage 2024 is neck in neck with years like 2021 and 2022. Heck, considering June in isolation, June 2024 accumulated 40% more GDD’s than June 2023.

measuring heat accumulation as “proxy” for harvest

Grower degree days are just one way to measure heat accumulation during the growing season. (If you want specifics, GDD are the daily average temperature, i.e. maximum + minimum temperature divided by two minus the base temperature, 50F). Anyhow, we tabulate the GDD’s each day to create a cumulative tally. Here I’ve tallied grower degree days from April 1st through July 8th, for vintages 2021, 2022, 2023, and 2024. And I knew what you’d ask next: “OK smarty-pants, just how many degree days do you need until harvest?” So I tabulated that metric, too.

Heat Accumulation Measured as Grower Degree Days: comparing vintage 2021-2024

All this data is the long way of telling you that vintage 2024 sits squarely in the “new normal” for Sonoma County harvest season. Heat-wise and weather-wise, the 2024 growing season looks a lot like 2022 and 2021. Furthermore, this puts 2024 in pretty good company; the 2021’s are beautiful, and the very young 2022’s are starting to taste fantastic.

data is helpful but not absolute

We winegrowers can monitor grower degree days and average daily temperatures and hem and haw over historical data for budbreak and bloom and harvest. Each is a useful parameter. But in the end, we growers have very little control over the exact timing of harvest. Sure 110 days from bloom to harvest is a nifty back-of-the-napkin metric, but only Mother Nature controls the weather.

lastly, if it’s hot af where you live…

Lean into rose…

Slow, sexy rose swirl

As always, thank you for your support. As always, I always welcome your comments, questions, and insights. If you’re planning to visit Sonoma County, please consider adding Bruliam Wines to your itinerary. Reservations can be booked via the website (& Tock).

Finally, if you’ve read all the way through to the end I do have a small favor to ask. As a fan of Bruliam Wines, it would help me tremendously if you could post a Google review recounting your favorite Bruliam experience - be it at the winery, a restaurant, a tasting, or just opening a delicious bottle at home. Every 5-star review helps. Please click here to add your review!