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How This Winemaker Handles the Harvest at CAST Wines

Cover Image for How This Winemaker Handles the Harvest at CAST Wines
By Morgan Carter

With a chemical engineering degree in hand, Ashley Herzberg had initial planned to enter the medical field. However, she felt like something was missing. Looking to combine her love of both science and nature, she decided to volunteer for a harvest in Sonoma County. 17 years and hundreds of harvests and tastings later, Herzberg currently consults for a variety of wineries across the Sonoma County region, including CAST Wines. We caught up with Herzberg to talk about her draw to the industry, the changing vineyards, and the long haul that is the harvest season.

What was it that drew you to the wine industry?
Initially, I was pursuing a career in the medical field. I actually worked in a hospital during college, but something was missing. I grew up in the Lake Tahoe area—we were just such outdoorsy kids and I loved being outside. In thinking about a career, I felt like I needed something that was science based, used my chemical engineering degree, and was also tied to nature. Actually, one of my chemical engineering professors recommended this industry to me. I worked one harvest in Sonoma County and completely fell in love with the wine industry. It’s such a mix of science, being outside, and this level of artistry that engineers don’t always get to partake in. Getting to hold and drink the product that you made is really special.

You got your start working as a lab technician and lab manager at Owl Ridge Wine Services. How did that experience inform you as a winemaker? 
Owl Ridge was a custom crush facility. We had over 40 clients—so many winemakers, so many different styles. I got to see so many ways of doing winemaking. There’s a lot of personal touches, choices, and decisions that you can have influence over. After my first year I thought, “What would my style be? Who would I want to be as a winemaker?”

You currently work as a consulting winemaker and service a number of wineries across the Sonoma County region. What type of services do you offer? 
I do the same thing that a full-time winemaker would do, but I work for smaller brands that don’t necessarily need someone every day. I manage the vineyards—what we’re going to pick and when, the management during harvest—all the way to making the final wines and bottling. It’s a very busy job but very fulfilling.

CAST Wines
Crushing grapes at CAST Wines

Coming fresh off of the harvest season, what does a typical day in the life look like? 
Depending on the vineyard and the site, we pick either at 2 a.m., 4 a.m., or starting at daybreak around 6 a.m. For the 2 a.m. picks, I’m out there monitoring, seeing how it’s going. You don’t really know what the fruit is going to look like until you start. For the 2 a.m. picks, I don’t stay out for the whole pick, I’ll go home and sleep for a few hours. But for the 6 a.m. picks, I’ll roll right into my work day. I’ll be out in the vineyard until about nine, and then I’ll start heading to other vineyards to sample. That’s such a fun part of the day—walking up and down rows, pulling cluster samples, and tasting the grapes. After that, it’s heading to the winery for processing the grapes we picked that morning or tasting every single ferment.

When people think about winemaking, it sounds very glamorous—you’re tasting lots of wines, the dinners, the tastings. But there are very messy, very physical parts to the job.

What does the tasting portion look like?
Every active ferment gets tasted every single day. During the peak of harvest, it can take six to ten hours to go through every single lot when you have over 100 active ferments. As a consultant, I’m in multiple facilities, so I’m driving around tasting everything.

Shot of the vineyards at CAST Wines
CAST Wines, Geyersville, CA

What is something you think that people don’t fully understand about winemaking?
When people think about winemaking, it sounds very glamorous—you’re tasting lots of wines, the dinners, the tastings. But there are very messy, very physical parts to the job. The days during harvest can be up to 14 hours, that’s just how it is. The wines don’t stop, they don’t wait for you.

Over the past few years, wineries across California have had to deal with the impact of climate change,  including wildfires. How have you dealt with these issues? 
It is definitely a challenge that I didn’t know I was going to be facing when I started. We’ve had fires in 2017, 2019, and 2020. The 2017 and 2019 fires were very late in the season, so I didn’t lose anything those years. But in 2020, the smoke started settling into our grape growing areas. So we stopped picking rather than having smoke tainted wines. And that’s hard. To just walk away from those harvests is really painful.

Shot of the vineyards at CAST Wines
CAST Wines, Geyersville, CA

Has it affected how you approach the harvest?
I’m more keen on picking early rather than letting the grapes hang for another week because I think, ‘What if a fire starts?’ We want to get things off the vine and safely into the winery, just in case we have an adverse weather event.

What makes Sonoma County so special?
Sonoma County will always be where my heart is, there’s so much here. We’ve got the very rugged Sonoma Coast where there’s very extreme cold weather and fog. And then the inner valleys—Dry Creek Valley and Alexander Valley—are warm and you can grow sun loving, heat loving varietals there. And the whole Russian River Valley is where we get all the fog influence, but we also get the heat. Sonoma County is such a diverse region, more so than many regions in the whole world. I just absolutely love it here.

Image of winemaker Ashley Herzberg in a barrel/tasting room
Ashley Herzberg of CAST Wines

Is there a particular wine from CAST Wines that you love right now? 
CAST Wines has estate grown sparkling wines that are made out of zinfandel grapes, but they drink like a blanc de noir. They are made using méthode champenoise, so very traditionally made. I would love it if everyone could try them because it would change your mind about what grape varietals you can use for sparkling.


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