There are more than 5,000 different grape varieties in the world but June 21, 2012 is dedicated to just one: sauvignon blanc. With only 365 days in the year, not all grapes can be equally honored, but the major international varieties are beginning to fill up the calendar. For example, malbec has been allotted April 17, chardonnay May 26 and grenache September 23.

Today marks the third annual International Sauvignon Blanc Day, during which producers, retailers and consumers are encouraged to crack open a bottle of this crisp, vibrant white and participate in an online conversation on Twitter by following #SauvBlanc.

“This is an opportunity to join a global wine-tasting event,” said Michael Scholz, winemaker at Napa Valley’s St Supéry Estate Vineyards and Winery. “Get on Twitter or Facebook and join the worldwide conversation about sauvignon blanc.”

If you don't yet have a bottle to hand, we have compiled a list of the top ten most-searched-for sauvignon blancs on Wine-Searcher. It’s a battle between France and New Zealand for supremacy. Bordeaux takes the top two spots, but Marlborough’s Cloudy Bay is the only estate with two entries, including its barrel-fermented example, Te Koko.

Sarah Burton, winemaker at Cloudy Bay, believes sauvignon blanc’s lively style and its distinctive aromas, such as gooseberries, elder flowers and passion fruit, give the varietal widespread appeal. “It’s about crispness and freshness and is perfect when you sit down on a hot day. People are also really familiar with its flavors,” she told Wine-Searcher.

Wine Searcher’s Top 10 Sauvignon Blancs:

1. Château Margaux Pavillon Blanc du Chateau Margaux, Margaux, France
2. Domaine de Chevalier Blanc, Pessac-Leognan, France
3. Kim Crawford Sauvignon Blanc, Marlborough, New Zealand
4. Cloudy Bay Sauvignon Blanc, Marlborough, New Zealand
5. Château Smith Haut Lafitte Blanc, Pessac-Leognan, France
6. Didier Dagueneau Pouilly-Fumé Silex, Loire, France
7. Oyster Bay Sauvignon Blanc, Marlborough, New Zealand
8. Cloudy Bay Te Koko Sauvignon Blanc, Marlborough, New Zealand
9. Merry Edwards Winery Sauvignon Blanc, Russian River Valley, USA
10. Villa Maria Estate Private Bin Sauvignon Blanc, Marlborough, New Zealand

Duckhorn Vineyard and Grgich Hills Estate in the Napa Valley are among the wineries participating in the worldwide Twitter/Facebook discussion, which is running from 12.01 a.m. to 11.55 p.m. on June 21, Pacific Standard Time.