You've probably never heard of these tiny tasting rooms, but a visit to any of these boutique wineries is sure to be filled with tasty vino and one-on-one time with the winemakers.

St. Clair Brown Winery

This delightful urban winery sits so close to the downtown Napa Wine Train station that staff at the glass-enclosed tasting room have a tradition of waving at passengers rolling by. It's a virtual oasis, hidden behind a lavish culinary garden, with the winery itself right across the parking lot. Co-owners Laina Brown and Elaine St. Clair clearly have fun, as they sample and share their hand-numbered bottles of cabernet sauvignon, merlot, syrah, zinfandel, syrah rosé, chardonnay, sauvignon blanc, pinot grigio and muscat. And we mean tiny: less than 200 cases are made of each varietal. // 850 Vallejo Street (Napa), stclairebrownwinery.com

Suggested sip: 2011 Cabernet Sauvignon ($80)

Papapietro Perry Winery

You'd never guess, based on the simple decor of Papapietro's tasting room, that this label is highly-coveted among Pinot Noir and Zinfandel-lovers. Grab a seat at the polished wood bar, listen to the local tales from the friendly staff, and enjoy first-class tastings in Riedel glassware. For even more fun, reserve the Pinots on the Patio wine and cheese experience overlooking the vineyards (if you're lucky, winery owners Yolanda Papapietro and Bruce and Renae Perry may be hosting life jazz from Bay Area favorite, Brother Cat). // 4791 Dry Creek Road (Healdsburg), pappietro-perry.com

Suggested sip: 2013 Russian River Valley Pinot Noir ($53)

Kelly Fleming Wines

Start your tiny winery tour with a visit to Kelly Fleming Wines. The tour, led by Kelly Fleming herself, showcases the estate's natural volcanic rock wine caves and includes a leisurely tasting of high-end, limited production wines including estate cabernet sauvignon ($110), sauvignon blanc ($36) and cabernet sauvignon rosé ($36). You'll also hear about the vineyards, estate dogs, rescue donkeys, and every detail that went into the rock-clad, 3,000-case, Tuscan-style tasting salon. Visits are by appointment only and limited to eight guests per day. // 2339 Pickett Road (Calistoga), kellyflemingwines.com

Suggested sip: 2012 Big Pour Napa Red blend ($75)

BUMP Wine Cellars

This family-owned and operated boutique winery opened in downtown Sonoma earlier this year and focuses on small-lot, single-vineyard wines sourced from sustainably farmed vineyards throughout Sonoma County. Owners Georgie and Mieko run an elegant little tasting room off the Square, sleek with red brick walls, old vine trunks as wall décor, changing art shows, and cozy couches. But best of all is their personal attention and cheerful chatting. // 521 Broadway, Ste. A (Sonoma), bumpwine.com

Suggested sip: 2012 Bedrock Vineyard Zinfandel, Sonoma Valley ($36)

Twenty Rows

If you want to see a working winery in action, head to this showcase property in downtown Napa where you can wander amid the tanks and barrels while tasting. Owners Brian and Lori Nuss dress up the concrete floor space with flowers, dimmed lights and votive candles, and a jamming sound system for extra energy. And it's usually a party, with winemaker Brian sharing tall tales, and usually some dogs prancing about, too. // 880 Vallejo Street (Napa), twentyrows.com

Suggested sip: 2013 Twenty Rows Cabernet Sauvignon ($25)