Winery Barrel Sanitation and Smoke Taint: Practical Approaches with Jim Duane, Winemaker at Seavey Vineyard
Jim Duane has been the winemaker at Seavey Vineyard in Conn Valley for almost 15 years and hosts the Inside Winemaking podcast, now with more than 192 episodes covering the technical side of wine production. He was on the ground in Napa during the October 2017 fires and made wine from smoke-affected fruit, which means his perspective on smoke taint is not theoretical. He has been working through the problem hands-on since it became unavoidable.
This is Part 2 of a two-part conversation with Lauren Heindel, picking up where Part 1 left off. Part 1 covered the fundamentals of wine faults during fermentation, including oxidation, volatile acidity, and Brettanomyces in barrel. This episode moves into barrel sanitation, the nuances of TCA, and what wineries are actually doing about smoke taint, along with the operational realities of running a small estate operation.
Smoke taint, TCA, and barrel management all share something in common with most real-world winemaking problems: the solutions that get marketed most aggressively are not always the most effective, and the actual best practices often require more patience and precision than the marketing suggests. Jim’s approach to all of them is grounded in what he has seen work and what he has seen fail in his own cellar.
In this episode, we cover:
Why ozone is a poor barrel sanitizer for Brettanomyces, and why many ozone generators are not producing what their owners think they are
The barrel sanitation approach Jim actually uses, and which agents are best suited for which surfaces in the cellar
How TCA enters a winery, why it is the fault least connected to winemaking process, and how to do atmospheric testing before it becomes a problem
What smoke taint actually smells and feels like, and why it is fundamentally different from the pleasant smoke notes some wines are known for
The two components of smoke taint (aroma and mouthfeel) and why different remediation technologies address each one differently
Why reverse osmosis can produce wine that tastes clean at bottling and comes back tainted three weeks later in bottle
How Seavey compressed a seven-day harvest window to two days in response to wildfire risk
Barrel sanitation: why ozone falls short and what actually works
Jim’s position on ozone as a barrel sanitizer is direct: he thinks it is ineffective for the problem it is most often used to solve. The structural issue is that ozone is a surface sanitizer. It kills cells it physically contacts, but wood is not a flat, contactable surface. Barrels are full of cracks, crevices, and spaces between staves where Brettanomyces cells lodge, and ozone does not penetrate into the wood. It has such a short half-life that by the time it reaches anything below the immediate surface, it has essentially degraded.
There is a second problem compounding the first. Ozone generators are supposed to produce around five or six ppm to be effective. Many of them fall out of calibration without anyone noticing, and if the winery is not regularly testing the water, they may be running nothing more than cold water with no active ozone at all. Jim has encountered this at multiple wineries.
I think ozone's a joke when it comes to barrels. Ozone is a surface sanitizer, so anything that physically touches a Brettanomyces cell, yeah it may kill that cell, but is that ozone getting down a couple millimeters into the wood and all the nooks and crannies? And ozone is such a short half-life that it's kind of there and gone.
Jim Duane , Winemaker
Seavey Vineyard
For barrels, steam is the most effective sanitizer Jim has found. It penetrates deeper into wood than surface agents and kills Brettanomyces and other spoilage organisms in a way that surface contact alone cannot replicate. For everything else in the cellar, stainless steel, hoses, pumps, fittings, and lab equipment, peracetic acid is his preferred agent. It cannot be used on wood, but for non-porous surfaces it is thorough and effective. When a Brett infection is active in the cellar, stopping the spread to clean wines means keeping peracetic acid in regular use on all the equipment that moves between lots.
If your winery uses an ozone generator, test the output periodically with the kit that comes with the unit. Most ozone systems have a simple test to confirm they are producing at the target ppm level. If the generator is not producing ozone at specification, using it for barrel treatment is not accomplishing anything for Brett prevention. Steam, even if less convenient, is the more reliable option for wood surfaces.
TCA: the fault that lives in your winery, not your process
TCA, trichloroanisole, is cork taint. It is the compound responsible for the musty, wet cardboard, and baby carrot smell that renders a wine undrinkable, and it is detectable by most people at concentrations below five parts per trillion. That level of sensitivity is what makes it such a consequential fault: you can have a wine that performs perfectly through your entire production process and have it ruined by something introduced at the very last step.
The cork industry has done significant work over the last twenty years to reduce TCA incidence by removing chlorine from its production processes, since the trichloroani- prefix reflects the three chlorine atoms in the molecule. Most winery-related TCA exposure today comes not from corks but from the winery environment itself. Wood of any kind in or near the production facility can harbor the molecule, especially in older wineries that used chlorine-based cleaners before the industry moved away from them. Pallets are a common source. Occasionally a bad stave in an oak barrel brings it in. None of these vectors are within a winemaker’s direct control the way fermentation management or SO2 timing is.
I don't wanna rest on our laurels and get complacent because sometimes TCA can come in on wood pallets, and occasionally it can come in on oak barrels as well. It's rare and a lot of oak coopers are testing for this, but sometimes all it takes is one bad stave.
Jim Duane , Winemaker
Seavey Vineyard
The practical management tool is atmospheric testing. ETS Laboratories offers test kits that function like absorption traps: small aluminum trays filled with absorbent material are placed around the production environment and left for a weekend, then collected and sent to the lab for analysis. The results tell you whether TCA is present at detectable levels in your winery environment before it gets into your wine. Jim runs this test annually at Seavey, not because he has had a TCA problem, but because that is the kind of vigilance the molecule requires.
Do not limit TCA atmospheric testing to inside the winery. Test near anywhere incoming wood materials are staged, including pallet areas and barrel storage zones. TCA can arrive on a single piece of wood and spread through the environment. Catching the presence of the molecule in the ambient air is far easier and less damaging than finding it in a finished wine.
Smoke taint: a problem with no clean solution
Jim’s first serious encounter with smoke taint was October 8, 2017, when fires broke out in Napa and he still had half of Seavey’s Cabernet unpicked on the vine. He made wine from those grapes because he had to learn, but none of it made it to bottle. His description of what smoke taint actually tastes like is worth quoting before getting into remediation, because a lot of the conversation about smoke taint in winemaking circles undersells how severe the fault is. It is not a whiff of smoke or a campfire quality that some consumers might even find appealing. It is burnt plastic and ashtray, and it produces aggressive bitterness and harsh phenolics in the mouth that no amount of winemaking finesse resolves on its own.
The mechanism of smoke taint makes it uniquely difficult to treat. Smoke compounds exist in wine in two states: free and bound. The free compounds are what carry the aroma and are perceptible at tasting. The bound compounds are conjugated to other molecules in the wine and do not register immediately. The problem is that free and bound forms are in equilibrium, which means if you remove the free compounds, the equilibrium shifts and some of the bound forms become free over time. The smoke comes back.
Smoke is complicated because it's kind of in this equilibrium between free and bound forms and it's going back and forth. As winemakers, we really only have access to remove the free compounds. If you remove those, then the equation shifts, so some of the bound becomes free. Oftentimes the smoke flavors will come back even after you feel like they've been removed.
Jim Duane , Winemaker
Seavey Vineyard
Charcoal fining addresses the aromatic side of the problem. Carbon is not selective: it adsorbs smoke compounds, but it also strips out wine character in the process. The result is a cleaner-smelling wine that is also a lower-quality wine. Reverse osmosis separates the wine into components, passes the permeate through a charcoal filter to remove free aromatic compounds, and recombines. The horror story Jim describes is real: RO can produce wine that tastes clean and fruit-forward the day it is treated and shows smoke three weeks later in bottle, after the bound-to-free conversion has shifted the equilibrium again. Bottling immediately after RO treatment without allowing time to assess whether the smoke returns is a documented failure mode.
SRX membrane technology from Vin Sci addresses a different problem. It does not remove smoke aromatics. What it does is strip the harsh bitterness and difficult tannin structure that smoke taint produces in the mouthfeel. You can trial it at bench scale with a single bottle before committing to a full-batch treatment, which makes it a lower-risk entry point for assessment. Jim found the before-and-after tasting comparison striking in terms of how much it improved the tactile experience of the wine without addressing the aromatic dimension.
Smoke taint has two components: aroma and mouthfeel. And unfortunately, the tools to treat each are different.
Jim Duane , Winemaker
Seavey Vineyard
If you are considering reverse osmosis for smoke taint remediation, do not bottle immediately after treatment. Allow a minimum of several weeks and taste the wine again before making the bottling decision. The bound-to-free equilibrium shift takes time to manifest, and a wine that smells clean the week after RO treatment may look very different a month later. The investment in patience before bottling is far less costly than discovering the taint has returned in bottle.
Operating a small winery: labor, space, and the cash flow cycle
The final section of the conversation covers the operational realities that are specific to small estate wineries and that do not come up as often in technical discussions. Jim thinks about labor constantly, and his framing of the challenge is precise: the need for workforce at harvest is a short, intense surge, and the mechanism to create that surge does not exist for small wineries the way it does at large operations. Doubling or tripling your team for the six to eight weeks of harvest and then scaling back down requires finding people willing to work a full-time but temporary seasonal job, and that is not a simple hiring problem.
The facility constraint is equally persistent. Most small wineries use the same physical space for fermentation, barrel aging, blending, and bottling, which means every operational phase requires reorganizing the space around the next one. Jim’s description of winemakers who become expert forklift operators and creative stackers of equipment is not a joke: it is a genuine skill required to run a small cellar efficiently.
Cash flow for DTC-focused wineries creates a rhythm that requires planning around the gaps. Seavey ships to its wine club in fall and spring. The period from late spring through summer and early fall involves winery visits but no large club shipments, and bridging that six-month period requires either capital reserves or bridge financing. Jim’s point about understanding the full-year cycle, not just the winemaking calendar, is something a lot of small winery operators learn the hard way.
You have to be very smart about not only how much money you're gonna spend but when you're gonna spend that money. Thinking about the cycles of the year, not only winemaking but cycles of sales, is really important to small wineries that are probably gonna be more beholden to uneven cash flows throughout the year.
Jim Duane , Winemaker
Seavey Vineyard
The response Seavey made to wildfire risk connects directly to the operational theme. After 2017, they upgraded their harvest equipment, switching from 35-pound picking bins to macro bins that allow the vineyard team to work faster, and added processing capacity in the winery to handle fruit rapidly. The outcome: a seven-day pick window compressed to two. In a smoke event, the priority is getting the fruit off the vine and through processing as fast as possible. That capability requires capital investment and planning that happens well before fire season, not in response to an active smoke event.
If your winery is DTC-dependent with seasonal shipment windows, map your cash flow by month before building your operating budget for the year. The months with no club shipments are predictable, and the bridge financing needs are equally predictable if you plan for them. Wineries that end up in distress during the dry months are often ones where the cash flow pattern was known but not planned around. The lean months are a feature of the DTC model, not a surprise.
Watch or listen to the full episode on YouTube | Spotify | Apple Podcasts.
For more conversations like this, subscribe to Expert Talks and join The Punchdown, InnoVint’s online community for wine professionals.
Frequently Asked Questions about Winery Barrel Sanitation and Smoke Taint
Does ozone work for barrel sanitation in wineries? +
Ozone is not effective for sanitizing wine barrels against Brettanomyces. It is a surface sanitizer that kills cells it physically contacts, but it does not penetrate into the wood where Brett cells reside in crevices and between staves. Ozone also has a very short half-life, degrading quickly before it can reach deeper into the wood. Steam is the preferred barrel sanitizer for killing Brettanomyces because it penetrates wood more effectively. Ozone can be useful for sanitizing stainless steel tanks and other non-porous surfaces, but only if the generator is regularly tested and confirmed to be producing at the correct parts-per-million concentration.
What is TCA in wine and how do wineries prevent it? +
TCA (trichloroanisole) is the compound responsible for cork taint, producing a musty, wet cardboard or baby carrot aroma detectable at less than five parts per trillion. It is not a winemaking process fault but an environmental one, typically originating from chlorine-treated wood in the winery, pallets, or occasionally oak barrels. Prevention involves eliminating chlorine from the winery entirely, including filtering municipal water to remove chlorine before use. Annual atmospheric testing using absorbent traps placed around the production facility and analyzed by a laboratory detects the presence of TCA in the environment before it contaminates wine. Once TCA is in a wine, it is a deal-breaking fault with no remediation.
How do wineries manage smoke taint in wine? +
Smoke taint remediation requires addressing two separate problems: aromatic compounds and mouthfeel. Charcoal fining removes some aromatic smoke compounds but is non-selective and strips wine character in the process. Reverse osmosis separates and treats the free aromatic compounds but does not address bound compounds, which convert back to free over time, meaning smoke taint can return weeks after treatment. SRX membrane technology (from Vin Sci) addresses the mouthfeel component, specifically the harsh bitterness and difficult tannins, without targeting the aromatic side. Most severely smoke-tainted wines require a combination of approaches and close monitoring before bottling. The most effective prevention is getting grapes harvested and processed as quickly as possible after a smoke event.
What causes smoke taint to come back after reverse osmosis treatment? +
Smoke compounds in wine exist in two forms: free and bound. Free compounds are perceptible to smell and are what reverse osmosis targets. Bound compounds are chemically conjugated to other wine molecules and are not immediately detectable. After treatment removes the free compounds, the equilibrium between free and bound forms shifts and some bound compounds convert back to free over time. This is why wines that taste clean immediately after RO can show smoke taint again weeks later, particularly after bottling. Allowing adequate time between RO treatment and bottling, and tasting again before the bottling decision, is necessary to avoid discovering the problem in the bottle.
What is the best approach for small wineries to prepare for wildfire smoke risk? +
Small wineries in smoke-prone regions can reduce smoke taint exposure primarily by moving quickly at harvest. This requires having the processing capacity, both in the vineyard with faster harvesting equipment and in the winery with faster receiving equipment, to compress the pick window significantly when smoke is present. Before harvest season, small-scale fermentation trials using UC Davis protocols can test whether grapes have absorbed smoke compounds after a smoke event, giving winemakers the information they need to make picking and processing decisions. Spray-on vineyard coatings and barrier technologies are still in development and have not yet produced a proven field solution.