By Tan Vinh / Seattle Times features reporter

For all the love that shoppers give to the obvious bargains at Costco — the $1.50 hot dog-and-soda combo, the $4.99 rotisserie chicken — there’s a deal at the shoppers’ warehouse that’s less well-known: Costco’s private-label line of wines.

They are perfect for those planning a cost-effective and delicious New Year’s Eve party.

Costco boasts more than two dozen wines under its Kirkland label, and they hail from some of the most prestigious wine-growing regions in America, including Napa and the Willamette Valley.

As the nation’s largest wine retailer, Costco prides itself on not marking up any of its wines by more than 15 percent. Add in their surprising quality, and the Kirkland reds and whites are arguably some of the best wine deals in the country. Several bartenders and restaurateurs over the years have told me that the Kirkland wines are some of the best-kept secrets in the state.

I recently did a blind tasting comparing Kirkland’s $19.99 Signature Brut Champagne to a handful of others in the $50-$60 range. The Kirkland Signature was just as good, if not better, than others that cost at least twice as much.

Were there more gems stashed near the crates of croissants and the 30-roll packages of toilet paper? We had to know.

We reached out to Owen Bargreen, a certified Level Two sommelier from Seattle, who had sampled two dozen Kirkland reds and whites in October. He has the best palate of any wine connoisseur in Seattle I’ve come across.

Our question for him was simple: Which cases of Kirkland vino are truly worth seeking out during a Costco trip, in between eating free samples of jalapeño-cheese sausage? To be clear, we weren’t looking for a reboot of “Two Buck Chuck,” that Trader Joe’s plonk of years’ ago fame that was as offensive as it was cheap. We wanted whites we’d actually offer to house guests and reds we’d pair with a steak au poivre.

Bargreen’s first tip: When consumers think of Costco wines, they often look for the $6.99 bottles. But Bargreen advises bargain hunters to reach deeper into their pocketbooks to buy Kirkland bottles in the $15-$19 range; international reds and whites are the real gems, he said.

Below are Bargreen’s top five Kirkland wine picks, including how he rated the wine on a 100-point scale and tasting notes that he wrote up on his Washington Wine blog.

Sommelier Owen Bargreen found a Kirkland red from Spain that was “outrageously good value” among the two dozen he tasted.

Kirkland Signature 2012 Gran Reserva Ribera Del Duero ($15.99); score 92 out of 100

“Most Gran Reserva from that region cost more than $50,” Bargreen said of the Spanish red. “I don’t know how they actually got a Gran Reserva at this price point. Its ($15.99 price) is almost like a mistake,” as if some worker slapped on the wrong price tag. “The cool thing is, not only is it a Gran Reserva at a low price, but it’s from a good vintage. That makes the price even more remarkable.”

Bargreen’s tasting note: “I am very impressed with this great new release that shows some outrageously good value. This 100 percent tempranillo wine begins with toasty oak on the nose with prune and roasted dates. The minerality is really nice as the wine shows a good tension and sense of place. Black fruits and a touch of chocolate dominate the palate. This is a beautiful wine.” Ready to drink between 2018 and 2028.

Kirkland Signature Brut Champagne ($19.99); score 90

“There is literally no Champagne at that price point,” said Bargreen of the Champagne, which had held its own in my own blind tasting. “The closest thing to that is Nicolas Feuillatte, and that is still more expensive than Kirkland Champagne.”

Tasting note: “The Brut Champagne by Kirkland Signature is a blend of pinot noir, chardonnay and pinot meunier sourced from vineyards located in Verzenay. The wine starts off with lovely diatomaceous earth followed by lemon curd and brioche on the nose. The palate shows really nice citrus fruit with kumquat, lemon oil, sourdough bread and a light musty earth flavor. Dense and layered, this is a simply outstanding effort that is a one-of-a-kind value. Drink 2018-2024.”

Kirkland Signature 2016 Cuvee de Nalys Chateauneuf-du-Pape ($17.99); score 90

“Most Chateauneuf-du-Pape are $30 to $40 minimum,” Bargreen said.

Tasting note: The wine needs more than a one-hour decant to fully evolve. This begins with delicate aromas of red currant, red-raspberry cordial, rose petal and suggestions of Provençal herbs that build in the glass. Red-currant jelly, Provençal herbs and wet stone with cherry-candy flavors all mingle in the glass. A head-turning value, showing some bright acidity, this will continue to evolve well over the next decade. Drink 2018-2026.”

Kirkland Signature 2018 Ti Point sauvignon blanc ($6.99); score 90

OK, you’re a cheapskate. But if you still refuse to pay more than $7 for a wine at Costco, you’re in luck: This $6.99 New Zealand white made Bargreen’s cut.

Tasting note: “This is slightly sweet on the palate and screams pyrazines on the nose. Bright and fresh, this is highly refreshing and satisfying. Drink 2018-2022.”

Kirkland Signature 2015 Signature Series Columbia Valley red wine ($16.99); score 90

This is the only local wine to make Bargreen’s top five.

Tasting note: “Made by superstar winemaker Gilles Nicault, this starts off with a bouquet of milk chocolate, roasted dates and black-cherry cordial. The palate comes off a touch sweet, showing a pillowy mouthfeel. The core is quite dense with dark fruits and chocolate tones rounding out this excellent wine. Drink 2018-2024.”

You can also check out Bargreen’s complete ranking of Costco wines at his blog washingtonwineblog.com.