I recently spent a week in Sonoma with 32 other Master of Wine hopefuls, blind tasting until our palates gave out and getting thoroughly into the weeds on the minutiae of every facet of the wine business (seriously – I had one conversation about using micro-imprinted plastic pellets to remove smoke taint that stretched well over an hour). One topic that came up regularly and sparked furious debate was the rise of intentional reduction in high-end Chardonnay production around the world. It struck me (like a struck match, perhaps) that even among professionals, many of the underlying elements of the topic were not well understood. What is reduction? What does it smell and taste like? Is it a fault or a feature of high-end Chardonnay? Is there a difference between “good” and “bad” reduction? Which producers should one seek out (or avoid) because of their reductive tendencies? All this and more below.
The Nerdy Details – What, When, and How
The truth is that wine reduction isn’t really reduction. Strictly speaking, chemical reduction is when an atom gains an electron in a chemical reaction, as opposed to losing an electron (oxidation). I’m no chemist, so suffice it to say that isn’t the whole picture, but it’s a decent simplification. The aroma and flavor compounds we refer to when we talk about reduction in winemaking aren’t actually “reduced” in a chemical sense, but we call them reductive because they occur most frequently when we protect a wine from oxidation. They are really a group of compounds called volatile sulfur compounds (VSCs).
The category of VSCs is broad, and includes universally-hated aromas like those caused by hydrogen sulfide (rotten egg, dirty drain), divisive aromas like those caused by methanethiol and ethanethiol (cabbage, burnt rubber) and even traditional “varietal” aromas like the thiols associated with Sauvignon Blanc (particularly 3MH, the thiol responsible for the grapefruit character). Hydrogen sulfide, methanethiol, and ethanethiol are all caused by stressed-out yeast metabolism. Basically the yeast panics when it lacks the oxygen needed to function normally, and it turns on alternative metabolic pathways that utilize nitrogen compounds in the grape must to survive. Some VSCs are byproducts of those alternate pathways. The VSCs in Sauvignon Blanc are more about the thiol precursors present in the Sauvignon Blanc grape itself, and tend to occur even in more typical, healthy ferments.
But when we’re talking about high-end Chardonnay, the holy grail of volatile sulfur compounds is Phenylmethanethiol (PMT if, like me, you get a headache even thinking about pronouncing that word). PMT isn’t produced directly by stressed-out yeast. Instead, it occurs when hydrogen sulfide (that nasty rotten egg smell produced by stressed-out yeast) and benzaldehyde, another compound produced during primary fermentation that smells like almonds, react with one another, typically after fermentation is over. If you add oxygen to the mix after fermentation (either through sparging with O2, rough transfer of the juice to barrel, or simply aging in barrels with a high oxygen transfer rate), that hydrogen sulfide oxidizes, making it no longer able to react with the benzaldehyde. Bye-bye, flinty goodness.
If you want that PMT to form (as so many top Chardonnay producers seem to these days), you need to protect the wine from oxygen both during fermentation (so that the yeast produce hydrogen sulfide) and after fermentation (so that the hydrogen sulfide doesn’t oxidize before it can react with benzaldehyde), which is why you’ll see heavy lees usage in basically all the wineries that want PMT in their finished wines. Traditionally, the heaviest lees were allowed to settle after fermentation and were left behind when racking into barrel, but if you ask folks like Brian Sieve at Domaine de Montille, he “get[s] in [the fermentation tank] and scrapes every last speck of lees into the barrels”, particularly on the higher-end whites from historic parcels. Lees gobble up all available oxygen, protecting the wine from oxidation, and allowing PMT to form.
A Tale of Three Legends
Putting it simply, many winemakers will say that PMT (more often they’ll refer to the aromas – struck match, flint, smokiness) is the “good” reduction, while compounds like H2S, methanethiol, and ethanethiol are the “bad” reduction. Leaving aside the fact that it’s not that simple (the “bad” reduction in small enough quantities can be either undetectable or perhaps even positive for complexity), the bigger question is, “Who says that flinty reduction is a good thing?” Like the overuse of oak, concentrated PMT tends to take over the nose of a wine, and it can mask the fruit on the nose when the wines are young. Some tasters absolutely hate it, while others pay through the nose for it. How did we get here?
Many Burgundy enthusiasts will point to the dreaded “premox” era as the origin story for reduction in high-end Chardonnay. The story makes sense: a changing climate and bad corks caused expensive Chardonnays to oxidize prematurely, which led to angry customers, which led to far more protection against oxygen in the wineries, which led to PMT in the wines. But the story has some inconvenient plot holes. For one thing, we know when the premox era began: 1995/96, first tasted in the ‘96s around five years later (according to Jancis Robinson). But if you look at that same critic’s notes on some of the usual suspects like Domaine Leflaive, you can find clear descriptions of PMT prior to and during that era, and even some that suggest it was already a calling card of the estate: “Smoky reductive nose” (’92 Bâtard), “Characteristically reduced nose” (’96 Clavoillon). This suggests both that premox was possible even when the wine was once “reductive” (crystal clear on the ’09 Pucelles – one note in 2010 that says it “exhibit[s] the Leflaive trademark struck-match character on the nose”, then another in 2018 on the same wine that calls it “heavy and foot-dragging”), and that it was already a characteristic of the estate long before the early-2000s reaction against premox.
I’m suggesting a slightly more commercial origin for the modern reduction craze. Three iconic producers are well-known for their reductive tendencies, even before the premox era: Leflaive, Coche-Dury, and Roulot. These producers occupy some of the most enviable terroir in Burgundy and have long commanded premium prices. Their compelling stories, rare parcels, and distinctive taste (caused in part by PMT) made them prime candidates for export by high-end specialty importers in markets like the US and UK, and by the modern era they were not only cemented as legends but also almost completely unattainable for more entry-level consumers. What happened next is simple: ambitious producers around the world wanted to achieve the flavors (and price points) of those legendary three, so they started imitating their winemaking techniques. One such technique now seen round the globe is even colloquially named after one of the three – the Roulot method – the practice of returning the wine to stainless steel tank after barrel age, while still retaining those antioxidant lees. While the barrel aging allows some oxygen ingress (mostly sequestered by the lees in this case), the stainless is fully anaerobic, maximizing that PMT synthesis.
The Children of Burgundy
All around the world, ambitious Chardonnay producers are now adopting the production methods pioneered by icons like Leflaive and Roulot in search of “good” reduction. Vasse Felix in Australia’s Margaret River is about as far geographically as one can get from Walter Scott in Oregon’s Willamette Valley. But the Chardonnay produced in these far-flung climes tastes remarkably similar, punctuated by an intense, flinty nose that can eclipse the fruit in youth. “These are ten-plus-year wines, and they need that intensity of the reductive notes when they’re young,” Ken Pahlow told me on a visit to Walter Scott during the 2025 harvest.
The rise of reductive Chardonnay worldwide puts into question one of the wine world’s sacred cows: terroir. If it turns out that making concentrated, intensely mineral* Chardonnay is more a function of winemaking than hallowed dirt, what will happen to the mystique around certain parcels in Burgundy whose purchase requires a sultan’s ransom? Reimagined comparative blind tastings à la “The Judgement of Paris” will perhaps include more than just US wines in future decades, pitting Chilean, Australian, and New Zealand examples against whispered names like Meursault Perrières and Chevalier-Montrachet. Whatever the result, we’d like to be invited.
Where do you stand on reduction in high-end Chardonnay? Are you a flint-follower? Or is matchstick a malodorous mistake? Drop us a line with your thoughts. Meanwhile here is a non-exhaustive list of producers whose wines have recently struck us as distinctly flinty:
Burgundy
Domaine Antoine Jobard, Meursault
Domaine Rémi Jobard, Meursault
Domaine Leflaive, Puligny-Montrachet
Pierre-Yves Colin-Morey, Chassagne-Montrachet
USA
Bethel Heights, Willamette Valley
Violin Wines, Willamette Valley
Walter Scott, Willamette Valley
Australia
Bird on a Wire, Yarra Valley
Giant Steps, Yarra Valley
Tolpuddle, Tasmania
New Zealand
Bell Hill, Canterbury
Footnotes
* Not to open up another can of worms, but the term “minerality” has been shown to correlate with reductive compounds in a systematic review of organoleptic studies – “The science of minerality”, Hui-Chung Tai & Evmorfia Kostaki, 2025