I’m standing underneath an arched white tent the size of a football field. Tables are covered with wine bottles and fresh hydrangeas. A strange, loud pulsing like a heartbeat is coming through the loudspeakers. And all around me, winemakers are sitting at the edge of their seats.

“Bid $6,000! Bid $7,000! Can I get $7,500?” yells the auctioneer, sweat pouring from his face. “You want this wine!”

I’m at the Sonoma County Barrel Auction, a yearly fête where experienced barrel tasters and Sonoma County aficionados can bid on exclusive wines by the barrel, like Lot #2, an exclusive five cases of Petite Sirah from Amapola Creek Vineyards and Winery.

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Auctioneer John Curley is competing with the pulsing soundtrack and driving the price up. Before long, sommeliers in sundresses and private buyers are putting their wine glasses down and their paddles up.

By the time Lot #6 rolls around, people are in the mood to spend. Benovia Winery in the Russian River AVA of Sonoma is known for delicate Pinot Noirs that are silky, smooth, and so light they’re almost transparent. From the starting bid at $2,500, Curley runs across the stage, yelling numbers at a breakneck pace as paddles are raised like Hail Mary passes from one side of the tent to another, driving bids up and up.

The thematic soundtrack returns and buyers keep going, entranced by Curley and trusting this lot, eventually driving the bid to $8,500. That’s $141.67 per bottle, in case you’re wondering.

This auction is exclusively for the wine trade, and especially for resellers of wine, like online stores, small retailers, and private buyers. Participating winemakers and wineries produce lots called “Never Before, Never Again” wines exclusively for this event. The proceeds benefit the promotion of the Sonoma region and their wines both locally and nationally.

The participants at the auction might drink a bottle or two from the lots they purchase, but their goal is to sell these bottles to collectors of Sonoma wines or exclusive restaurants, where these special-release wines carry a lot of prestige and high price tags. Essentially, well-known wineries and winemakers are counting on their names, reputations, and the resulting wines to raise thousands for the Sonoma region.

It might sound old school, but this isn’t an old boys’ club; it’s more like a playground. Master Sommeliers, thirsty journalists, T-shirt-clad winemakers, small owners of retail stores and online giants like wine.com are present for the event, which comes after an entire day of jovial barrel tastings and multi-course wine dinners. For an event that will garner $794,000 in sales, it is surprisingly laid back, fun, and educational.

Over the course of 90 lots, 50 barrel samples, and one unsuccessful $11,000 bid, here’s what I learned.

You Don’t Taste at a Barrel Tasting

For starters, you’re not tasting. You’re analyzing. The ultimate purpose of tasting wines from barrel or any other fermentation vessel is to assess how they’ll change and develop over time. “Barrel tasting is like looking at a sonogram of a baby,” explained winemaker Kathleen Inman of Inman Family Wines. “It’s a tool to make sure it has all the parts it needs.”

By parts, Inman means tannins, acid, fruit flavors, and the balance of all three. “We’re asking ourselves if the elements in each wine are sufficient, but remember, they aren’t finished, so these are definitely not wines for drinking.”

Again, you’re analyzing the components of the wine more than tasting it. For example, the tannins that make your mouth feel dry after a sip of wine are most intense just after a wine is made, and mellow out over time. Strong tannins are an indicator that a wine will age well for a long time, while a lack of tannins indicates a wine that’s ready to drink now. So if you’re shopping for wines to sell (like most patrons at barrel auctions) or to store in a private cellar, you’re looking for tannins that are stronger than what you normally drink.

The same goes for acid, which keeps wines refreshing and gives them the backbone they need to last over time. Unfinished barrel samples will have a lot of acid, sometimes tasting unpleasantly tart, which again will dissipate as wines continue to age in barrel and then bottle before the final consumer pops the cork.

“If any of those factors aren’t there, it’s like there’s a big hole in your baby, and that means things probably won’t end well,” Inman told me. “But, if it has all those parts, then I know it’s a safe buy because it will age.”

Take, for example, Lot #6, the Benovia Pinot Noir that went for $8,500. It had intense flavors and a dark color, but the cherry and fruit flavors echoed those of Benovia’s finished wines. The resemblance was clear, but the flavors were less polished, as buyers would expect.

You Always, Always Spit at a Barrel Tasting

As drinkers, that means we shouldn’t expect the wines to taste amazing at a barrel tasting. That’s not the point. Instead, we should look for stronger flavor characteristics — the metaphorical skeleton of a wine. This also means that when barrel tasting, you always spit.

Do Your Homework Before a Barrel Tasting

Finally, I discovered it’s important to know both the sonogram version of the wine and finished wines from the same producer or region to get the most out of barrel tasting. Year after year, wines from a certain vineyard or winemaker often share a family resemblance, revealing similar flavor characteristics.

So, if you’re embarking on a barrel tasting adventure at a specific winery, passport weekend, or stand-alone event like the Sonoma County Auction, it’s best to snap up a few finished bottles if you can beforehand. Taste them, see if you like them, and maybe jot down a note or two. Then, when barrel tasting, mentally compare the flavors to the finished wines.