Yesterday I got an early Christmas present - I found several bunches of Chardonnay with the beginning traces of powdery mildew! I freaked, and immediately went on a tear chopping off the afflicted clusters, but I gave up after discovering, that it was mostly just a berry or two in scattered bunches along the Northern side of the block. It seems to have blown in at the heads of several rows, possibly the result of spotty sulfuring along the row edges. Either way, it is a big concern.
We are days away from bunch closure and if the mildew gets inside the cluster, it will thrive in the dark, closed environment, eventually ruining the bunch. What are my options? If I let it take its course, it might flare up more intensely throughout the vineyard. The weather has been cool, there’s wind, and light precipitation is expected. These are the conditions favored by mildew. Not acting could lead to even more widespread infection. I could go around and cut out the afflicted berries, but I might miss some and that could lead to additional outbreaks.
My strategy for Chardonnay has been to keep a dense canopy in order to shade and cool the clusters. This shading strategy favors the type of flavors I am aiming for in the wine. Because Chardonnay is such a thin-skinned grape, too much sunlight, even reflected light, and high temperature, drive away chlorophyll and yellow up the berries, leading to sunburn. Sunburn, in turn, imparts a riper, more caramel flavor, something that I enjoy as an ingredient in the wine, but not as the main course.
But the dense canopy I’ve been developing blocks sunlight and wind. Were I to open it up I would reduce the mildew pressure –- the sun will help to clear it up and keep it away, and drying air will be able to blow through – but doing so brings the very real risk of sunburn and the possible loss of the flavors I am aiming for. Opening up the canopy will also insure that sulfur would actually get into the fruit zone, rather than merely ending up on the leaves when I spray.
It’s a quandary. The clock is ticking. The days have been cool. There’s been a fair bit of cloud cover, even some overcast. And the nights have had moist winds blowing off the ocean. Precipitation is on the horizon.
I live by signs and portents and a message arrives from a moldy odor in my washing machine. It has been idle for several days and the moisture in the closed dark space has been a breeding ground. I bleach the machine back to health and resolve to get radical in the vines.
I’ve been growing a jungle in the Chardonnay, allowing the vines to grow way beyond trellis height. There are places where they’ve crossed and tangled across the rows, and they are blocking the light and airflow. First up – topping the vines.
I head out in the early dawn covered from head to toe and plugged into music. A flock of White Tailed Black Cockatoos swoop dip across the edge of the vineyard, their conversation making crazy counterpoint to the song. I cut vine by vine with my secateurs, positioning the shoots to provide optimum canopy. I pause to pull away some laterals to let in more light, and notice some of leaves in the fruit zone are senescing –- they are yellowed and shriveling, indicating they are no longer acquiring nutrients for the vine. The shoots are also lignifying, another indication that the vines are far along.
After trimming back the jungle, I bring in a team of leaf-pluckers, having made the decision to expose the fruit to receive the morning sun. We are plucking specifically in the rows where I saw the mildew, plus a bit more. I figure that our close planting will serve to shield the grapes from the sun when it is overhead, as well as in the afternoon. The grapes will still be receiving lots of direct sun, although it will be the cooler morning sun, but inescapably this action will be inviting sunburn. When the nets go on, some of the light will be diffused, and perhaps that will reduce the sun’s effect.
I’ve tossed this decision around endlessly, concluding that this is what is being called for with these conditions. Some of the canopy will grow back in the lead-up to the hottest days of the summer, providing some shielding, the nets will diffuse some of the direct sunlight, and most importantly, we will end up with healthy fruit. There will be some sunburn, and depending on how much, I can drop fruit, vinify it separately, or let it flow and see where it goes. Our stunning 2012 Chardonnay has some rich glazed onion flavors that dance with mouthwatering nutty brioche. I didn’t expect we would achieve such richness, especially at a low alcohol, but I wouldn’t trade it – not for all the shaded grapes in the world.