Winemaking Mistakes No One Talks About – Part 2

Hot Takes & Hard Truths: Barrel Cleaning, TCA, and Smoke Taint

Every winemaker knows that harvest is a sprint, but what happens between vintages can have just as much impact on wine quality. In part 2 of our recent Expert Talks episode, we sat down with a seasoned Napa winemaker, Jim Duane, to talk barrel management, sanitation strategies, and some hot takes on ozone, TCA, and the increasingly urgent issue of smoke taint.

Barrel Cleaning + Proper Technique

There’s no shortage of opinions in the cellar, but one take came through loud and clear: ozone as a barrel sanitizer? Not worth the hype.

“Ozone is a surface sanitizer. Barrels are full of cracks, crevices, and microscopic pockets. Ozone just doesn’t get deep enough into the wood. And its half-life is so short—by the time it hits the surface, it’s basically gone.”

It’s not just about effectiveness. Many ozone systems fall out of calibration or stop producing the right ppm levels entirely. If you’re not testing your generator regularly, there’s a good chance you’re just spraying cold water, and what good is that?

Instead, Jim prefers steam as the gold standard for barrel sanitation. It penetrates deeply and effectively kills off Brettanomyces and other spoilage organisms. When it comes to the rest of the winery, peracetic acid is the go-to:

“You can’t use it on wood, but for stainless steel, hoses, fittings, lab gear—it’s my preferred sanitizing agent.”

TCA: The Deal-Breaker You Can’t Always Control

Trichloroanisole (TCA), better known as cork taint, is the heartbreak no winemaker wants to face. It’s not a flaw in your process—it’s a flaw in your environment or materials. And it’s powerful: some people can detect it at less than 5 parts per trillion.

While cork producers have made huge strides in reducing contamination (largely by removing chlorine from their processes), TCA can still sneak in through:

• Wood in your winery (especially older facilities that once used chlorine)
• Pallets and packaging
• Occasionally, oak barrels themselves

To stay ahead of it, Jim suggests to tests annually with atmospheric TCA kits, essentially setting out trays of absorbent material, collecting them after a weekend, and sending them to the lab for analysis.

“You don’t want to get complacent. TCA can come in on a single bad stave. It’s a molecule, not a microbe, once it’s in your winery, it’s hard to get out.”

Smoke Taint: The Wildfire Wrench in Your Harvest Plans

In a post-2017 world, wildfire smoke is a grim reality for winemakers across the West Coast. And unlike Brett or TCA, smoke taint starts in the vineyard, not the cellar.

“Smoke taint isn’t a little whiff of campfire,it’s ashtray, burnt plastic, bitterness, harsh phenolics. It’s gross.”

Here’s what you need to know:

Prevention & Testing

• Timing is critical. Grapes are most vulnerable around veraison.
• Micro-fermentations are the best way to test. UC Davis offers a protocol to help you assess smoke impact before harvest.
• Spray-on coatings and barrier technologies are in development, but there’s no proven solution yet.

Mitigation Through Speed

After the 2017 fires, Seavey Vineyards overhauled their harvest logistics to move fast—reducing a seven-day pick window to just two. The goal? Get the fruit off the vine and out of the smoke, fast.

In-Cellar Remediation

There’s no silver bullet, but a few strategies are helping reduce the damage:

• Charcoal fining can remove some smoke aromatics, but it’s non-selective and strips wine character.
• Reverse osmosis (RO) tackles free smoke compounds, but bound compounds can still release over time, meaning flavors can creep back.
• SRX membrane technology (from Vin Sci) shows promise for reducing harsh tannins and bitterness. You can even trial it with a single bottle before treating a full batch.

“Smoke taint has two components: aroma and mouthfeel. And unfortunately, the tools to treat each are different.”

Final Thoughts: No Room for Complacency

Whether it’s a lingering brett infection in a barrel, a rogue stave carrying TCA, or smoke settling on your cabernet just before harvest, sanitation and vigilance are everything. The tools we use matter. And so does our willingness to question them.

Want more expert insights like this?

Subscribe to Expert Talks and stay ahead of the curve in winemaking science, technology, and best practices.

Connect with Jim:

→ Inside Winemaking Podcast