Stewart Cellars & Guthrie Family WinesMichael Stewart founded Stewart Cellars in 2000 after a successful career in the technology industry in Texas.His son James joined in 2006, daughter Caroline in 2013, and Blair Guthrie became winemaker and vineyard manager in 2014.That same year, Blair and Caroline launched Guthrie Family Wines.Stewart Cellars farms Juliana Vineyard in Pope Valley within Napa Valley AVA and purchased Montecillo Vineyard in Sonoma’s Moon Mountain District in 2022, where new varietals are gradually being grafted.In 2024 Stewart Cellars produced approximately 9,000 cases across 22 wines, while Guthrie Family Wines is expanding from 2,000 to 4,000 cases in 2025.◆How did you get into winemaking — and Napa Valley?I’m originally from New Zealand and grew up in Rangiora, outside Christchurch. I wasn’t from a wine background at all — I was a rugby-playing beer drinker.After high school, I studied graphic design and worked as a designer. I’ve always been creative, but eventually realised the work was becoming too digital and computer-based for me. I wanted something more physical and hands-on.Wondering what to do next, I enrolled in an oenology and viticulture course at Tairawhiti Polytechnic in Gisborne (now the Eastern Institute of Technology). At first I imagined I’d simply be driving tractors in vineyards, but within weeks I realised winemaking could become a true creative outlet.◆Working at a custom crush wineryAfter graduating, I immediately moved to South Australia to work at a custom crush facility.It was an incredible opportunity because I helped build an entire winery operation while working alongside multiple consulting winemakers. I often say I gained eight years’ worth of experience in just three years.During this time, I completed a vintage internship at Paul Hobbs Winery in California. That’s where I met Caroline, now my wife, who was also interning there.After returning to Australia, one of our harvest workers suddenly pulled out, so I called Caroline and asked if she wanted to come work harvest with me. Six weeks later she arrived in South Australia, where we worked together at BK Wines and Adelaide Hills Winery.◆Putting down roots in Napa ValleyIn 2011 we returned to the United States and got married.I briefly worked for Paul Hobbs again before joining Kunde Winery in Sonoma, a fifth-generation family winery handling around 3,000 tonnes of fruit annually.Besides their own wines, Kunde also produced wines for Trader Joe’s, Costco, and various private labels, exposing me to a huge range of varietals and Californian winemaking philosophies.Meanwhile Caroline had already joined Stewart Cellars, the boutique winery founded by her father Michael Stewart in 2000.The winery was slowly growing, and by 2014 I officially joined full-time as winemaker while simultaneously launching Guthrie Family Wines as a side project.◆How do you approach winemaking for Stewart Cellars?Stewart Cellars is about producing “the best of the best” — sourcing exceptional fruit from exceptional vineyards and crafting premium wines with precision.We began with Napa Valley Cabernet Sauvignon and Bordeaux varietals, later expanding into Chardonnay, Pinot Noir, and Rosé from other regions while maintaining a strong focus on high-end, detailed winemaking.In Napa Valley, you compete against some of the world’s greatest winemakers, and I love that challenge.We start with outstanding fruit and aim to express both vineyard and vintage. My approach is relatively minimalist, but I think of myself as a sculptor: beginning with a large block of material and gradually refining it over time.This means slightly heavier extraction early on to build colour and tannin structure, followed by careful refinement through fermentation and barrel aging to shape balance and texture.Sourcing the best fruitFor many years Stewart Cellars purchased fruit rather than owning vineyards because Napa Valley land prices are extremely high.We turned this into an advantage by sourcing the best varietals from the best vineyard sites across multiple regions rather than being tied to a single estate.We can source Chardonnay from Sonoma Mountain, Cabernet Sauvignon from St. Helena, and Merlot from Chalk Hill, building long-term relationships with growers over many years.That’s important because understanding a vineyard properly takes time — often four or five years before you truly understand how it grows and when it should be harvested.Compared with Paul Hobbs, I generally harvest slightly earlier because I value freshness, terroir expression, and lower alcohol levels that pair better with fine dining.All fermentations are inoculated using carefully selected yeast strains developed over years of experience.The wines are aged unfiltered for extended periods, so it’s critical to complete fermentation fully and avoid any residual sugar that could create instability later.Barrel aging and blendingEvery Stewart wine except Rosé and Sauvignon Blanc sees French oak aging.The Bordeaux varietals spend around two years in barrel, while the Burgundian varieties spend approximately one year.The proportion of new oak depends heavily on the wine style:Pinot Noir: around 28–30% new oakBordeaux blends: 40–85% new oak depending on the wineAfter aging comes blending — the stage where everything comes together.Each barrel is initially treated as though it were a single-vineyard wine, and blending allows us to refine structure and fill in gaps.After bottling, the wines are further aged for 6–12 months before release.◆ A more natural approach for Guthrie Family WinesGuthrie Family Wines became my creative outlet — the “no rules” side of winemaking.The wines focus on organic fruit, minimal intervention, unusual varietals, and experimental fermentation methods.Where Stewart Cellars aims to create world-class polished wines, Guthrie Family explores texture, vibrancy, and immediacy.For Guthrie, I use organically grown fruit as a minimum requirement and prefer biodynamic or regenerative fruit whenever possible.In the winery, I try to avoid additions other than small amounts of sulphur.All fermentations are native, the fruit is hand-picked, and I don’t destem the fruit.White wines are whole-cluster pressed directly into fermentation vessels, while reds ferment as whole bunches with stems included.Because of the whole-cluster approach, many wines develop carbonic fermentation characteristics similar to Beaujolais.Fermentation is handled gently with foot stomping and minimal pump use.For whites, I often ferment at cool temperatures to preserve freshness and aromatics, particularly for Sauvignon Blanc and Vermentino.◆ Do the two brands influence each other?Absolutely.I constantly borrow ideas from both projects.As my confidence and experience have grown, Stewart Cellars has also evolved — slowly introducing larger-format barrels, partial native fermentations, and more whole-cluster fermentation in Pinot Noir and Grenache.We initially experimented with 10% whole clusters and recently increased this to 40%.Ultimately, we want to create wines and a winery culture built around elegance and longevity.PICK UP WINES with Blair's comments#12868 Stewart Napa Valley Cabernet Sauvignon 2021Origin: Napa Valley, CaliforniaVarietal: Cabernet SauvignonAlc.14.5%RRP incl. tax ￥21,450“This is the flagship wine of Stewart Cellars and our business card. It combines fruit from both the warmer northern Napa Valley and the cooler southern areas influenced by the ocean, balancing ripe plush tannins with herbal notes, rocky tannins, and acidity.”#12867 Stewart Tri-County Cabernet Sauvignon 2022Origin: Mendocino County, Sonoma County & Napa County, CaliforniaVarietal: Cabernet SauvignonAlc.14.5%RRP incl. tax ￥13,200“We wanted to create a Cabernet with the same quality as our Napa Valley Cabernet at a more accessible price point. Napa brings richness, Mendocino contributes red fruit freshness, and Sonoma adds earthy complexity and acidity.”#12866 Stewart Sonoma Mountain Chardonnay 2022Origin: Sonoma Mountain, CaliforniaVarietal: ChardonnayAlc.14.4%RRP incl. tax ￥10,450“The vineyards high on Sonoma Mountain receive heavy fog and cool air from the ocean, slowing ripening and producing concentrated fruit with remarkable character.”#12869 Guthrie Family Wines Pufferfish Red Wine 2022Origin: CaliforniaVarietal: Zinfandel 81% / Carignan 8% / Petite Sirah 6% / Chenin Blanc 5%Alc.14.1%RRP incl. tax ￥6,820“I make this wine to balance my creativity with the precision of Stewart Cellars. It’s unfined, unfiltered, lower in alcohol, vibrant, juicy, and designed as an ‘adult fruit punch.’”