You said winemakers get oak barrels from Slavonia. Where's that?

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Dear Dr. Vinny,
Where exactly in Eastern Europe is Slavonia? And are the oak barrels from there as ominous as the name sounds?
—Jeff C., Denville, N.J.
Dear Jeff,
Slavonia is a region in northeastern Croatia. Perhaps it will help if you think of it as a former part of Yugoslavia. Long before that, it was part of the Kingdom of Hungary, and the ancient Romans knew it as Pannonia.
Slavonian oak barrels are highly regarded in the wine community; in particular, they’re in fashion in Italy’s Piedmont region. I’ve heard that—like most wood used for barrels—the oak grown in the region is known for compact fibers and a tight grain. Most distinctively, Slavonian barrels tend to be large, and because of the ratio of the wine’s surface area to the inside of the barrel, larger barrels are said to impart more subtle flavors and softer tannins.
—Dr. Vinny