Over the weekend of May 16-17 this year, we experienced a brief but significant heat spike. Our vines had begun flowering the previous week (less than five percent), and temperatures had ranged from the 70s to the low 80s throughout the week.

As the mercury approached high 90s F., the vines had moved into full bloom. Grapevines are rather vulnerable during this period and require moderate conditions for complete pollination. Extremes of cool, hot, dry or wet weather can interrupt the process.

A good synonym for a vintage is “weather pattern.” Each growing season is a collection of fog and heat and wind and rain events. As wine grape growers, we can’t control the weather, but we do try to react to it in an appropriate manner to obtain the end product we want.

This year, as in 2007, the heat and subsequent rapid and incomplete flowering gave us little shot berries and … More…

We spent a day with Dr. Phil Freese recently. He’s formerly head of viticulture for Robert Mondavi Winery as well as professor of viticulture at the University of California. He and his wife, Zelma Long, who began her illustrious career making wine with Robert Mondavi and gained renown at Simi Winery, both consult with us.

We find their experience, expertise and the perspectives they bring very stimulating. Part of their role is to challenge us to continue to think creatively. One pitfall we try to guard against is falling into the same old ruts in our thinking and planning. Good enough is simply not good enough in the pursuit of the ultimate.

As we began our conversation, Phil commented on the smoke-filled skies from the many California wildfires during the past two months and … More…

Four days of 100-degree weather during the second week of July (the mercury reached 106 in the town of Sonoma on Tuesday the 8th) marked the fourth heat spike of the 2008 vintage. The first spike came in mid-May, accelerating the bloom period, and two others occurred on June 9th and 21st.

Fires continued to burn around the state of California, and the polluted air combined with the heat wave made working outside seem like standing in front of a blow dryer.

Just north of Sonoma on the Fourth of July, a hillside grass fire started with a spark from a mower and threatened residences as well as Hanzell Winery. Thanks to the swift response of firefighters, fixed-wing aircraft dropping slurry and a helicopter dropping water, the fire was put out after … More…

Yesterday I was out early, and the rising sun was just a small blood-red disk in a tan sky, the result of smoke and ash from more than 800 fires burning in California. The mountains around us are barely discernible in this haze, which resembles severe smog, and the sunlight has a brassy quality.

It’s cool now, but a week ago we had four days of 100-degree temperatures. That’s our third heat spike in what has been a fairly cool, windy and very dry season to date. We also had spikes in mid-May and early June, and this succession of heat events reminds me of the 2003 and 2004 vintages.

That said, the vineyards are showing nicely. We use two tools to monitor our water situation and evaluate the effectiveness of irrigations. The neutron probe tells us the levels of moisture stored in the soil. The pressure bomb, which we’ve had as … More…

Warm weather is upon us and is expected through the weekend and into next week. The mercury hit 96 degrees in Sonoma yesterday, but temperatures should be more moderate from today on. Walking the vineyards this week, I noticed some shatter – the failure of berries to develop due to incomplete pollination during flowering.

Shatter can be the result of too much heat or wind or moisture during bloom that prevents the setting of fruit. Timing is everything, as different sites, clones or selections and varieties develop at different rates. We expected some shatter with the onset of heat last month around bloom time as all the pent-up energy stored in the vines during the cool weather was unleashed in a growth spurt. We see elongated rachises (grape cluster axes) as a result of that spurt.

A little shatter is good for quality because it opens up the cluster, allowing berries to … More…