Just when you think you have a plan, the weather can really throw you a curve ball. The historic heatwave we’re experiencing has thrown harvest into chaos, a bit. Long story short: 4 days before our planned harvest, we had to find a new vineyard and new grapes. Luckily, we found some excellent Zinfandel up in Chalk Hill / Russian River at Notre Vue Estates. I’m not gonna lie: this is a tough year. Let me explain a few of the things we think about and why we (and every other winemaker out there) are sweating this heat wave in more ways than one.

There’s a few things in play with harvest: phenolic ripeness/maturity, sugar ripeness, and acid. This is a bit reductive, but broadly I’m going to talk in terms of brix for ripeness, pH for acids, and flavor for maturity. Generally, as sugar ripeness goes up, so does pH (in other words, grapes get less acidic). The first thing to know is that large swathes of California are pretty much perfect for growing grapes.

We don’t get rain in the summer. The days are consistently sunny, dry, and warm, but not too hot. And most importantly, outside the central valley and the inland empire and similar climates, it does not stay very hot at night. In the bay area and even up into the delta, the fog comes in at night and brings nice cool temperatures. So, grapes ripen a nice and reliable clip, about 1 brix a week, but they take long enough that the grapes have time to reach phenolic maturity before getting into high sugar ranges. Maturity is one of the big influences on flavor. This is something pretty much everyone has experienced: we’ve all had produce from the supermarket that was picked unripe and then ripened later. It may be sweet, but it doesn’t have the intensity of flavor you can get from fruit in season at a farmer’s market. It’s the same with grapes. The cool evenings help preserve acidity, too: it’s complicated, but it’s why all else being equal, hot days and hot nights lead to “flabby” (high pH) grapes.

Of course, phenolic ripeness can be a little controversial. Most mainstream red wine producers – especially cabernet producers – will pick a month or six weeks later than I would, and they’ll say it’s because they are waiting for phenolic ripeness. It’s true that you can have perfect brix (I like 23.5) and not have phenolic ripeness. That said, it depends on what you are looking for. The flavors in the grapes actually change. Get them on the early side of phenolic ripeness, inside the perfect window of ripe but not oxidized, and you will have the most amazing fresh, vibrant fruit flavors. Get them on the other side of that window and you are in the fast lane for jam, for the cooked flavors most people associate with “fruit forward” wines.

Now, let’s talk about 2022 harvest. There’s a few things in play: general, areas East of Napa- places like Suisun, Clarksburg, and similar will be about 4 weeks ahead of cooler climate areas like Carneros and the cooler parts of the Sonoma Coast. We picked our Suisun Zinfandel August 30th and a beautiful 23 brix. (Don’t get me wrong: sugar is just an easy way to talk about it. We go by taste!) Typical CA: phenolic ripeness and sugar ripeness were going hand in hand. But we’re also kind of weirdos in the modern market. Lots of producers will be waiting for higher brix and more jammy flavors. Meanwhile, in that Primitivo vineyard we won’t be sourcing from in Sonoma Carneros, the grapes were at about 19 brix and the flavor was still a bit on the supermarket produce side. The intense Zinfandel/Primitivo flavors weren’t there yet. Fast forward a week or two, and they’re getting closer. But there’s a heat wave. And heat waves stress vines. When the vines get stressed, grapes desiccate, shooting sugars up without increasing maturity. When the evenings stay warm, as they do in heatwaves like this, the acids respire away. So now you have high sugar, flavorless, flabby grapes. Damn! But growers can get the vines nice and hydrated before the heat hits, so the vines don’t totally get out of the grape ripening business, and you can get back on track after the fact. Maybe. Watering has its own considerations and complications, but when you start throwing in the insane temperatures we’re seeing – 117 in Marin County (!!)- there’s a good chance the vines just shut down and your grapes can be out there forever and just be turning into raisins without increasing in flavor.

So back to the Primitivo. I don’t think the water got on in time, and the grapes desiccated something awful, shooting up from 21 brix to 25 brix pretty much in the course of a few days. But in terms of maturity? Maybe tasting like 20 brix grapes. For other reasons, that grape contract didn’t work out, but if I didn’t say I wasn’t somewhat relieved, I’d be lying.

Instead, we found some fantastic actual Zinfandel up in Russian River. We are lousy with microclimates, here in CA, and for whatever reason, the grapes on the block we were buying from had phenolic ripeness that was somewhere more in what I’d associate with 22.5 brix in a normal year. Just inside the window of that fresh fruit flavor we’re looking for, no raising, maybe a little more delicate than what we’d normally go for, but as anyone who has had the Cuvee Minor Pinot we made in 2021, not any less flavorful for it. pH is around 3.4, which is beautiful and perfect, so the grapes have the acid to give the wine some backbone and really make sure you have time to experience the wonderful fruit flavors.

Of course, after we crush it and soak it, we are likely to see sugars around 27 or 28 brix just from the desiccation (there’s no way to escape it totally, and Zinfandel is notorious for it) so we’ll likely add some water back in to make up for it and make sure the yeast don’t choke and die on high sugars. But yeast and fermentation is a discussion of another post!