Sparkling wine continues to be a strong category and is one of the top contributors to beverage alcohol growth. So your editors sifted through the 2015 Winemetrics report to find the top producers in the category. And in looking at the top by-the-bottle (BTB) sparkling wine producers, several have a tight grip on the top spots, with the first six positions of the top 20 locked in place from 2014 to 2015.