Never mind the Strauss waltz about the beautiful blue Danube. Is it beautiful? Yes. Blue? No. The wines along the river, on the other hand, are striking shades of red and yellow. They are the products of the nine winemaking countries the Danube passes as it flows nearly 1,800 miles from Germany to the Black Sea.

Some of the wines are quite familiar to Americans. Others, long hidden behind the Iron Curtin, have only recently begun to appear in the States. Cruising along the most dominant of the Danube’s wine countries on Ama Waterways’ newest ship, AmaCerto, I sailed north from Budapest to Germany, drinking the wines of the countries whose shores we passed.

Through Hungarian waters, we drank Hungarian wines. The most interesting white, made from Olaszrizling, Hungary’s most heavily planted grape, was dry with a fruity aroma reminiscent of green apples. Often called Welschriesling and unrelated to Germany’s Riesling, it grows in six of the Danube wine countries.

Egri Bikavér, Hungary’s most famous red wine and long popular in the United States, translates to “Bull’s Blood.” Considering its deep color, full body and robust flavors, it is well-named, a worthy match to the beef tenderloin served with it that evening.

Hungary is also internationally known for Tokay, its glorious dessert wine whose sweetness is measured in puttonyos, the sweetest being six puttonyos. Never pass an opportunity to taste one.

From Hungary, we sailed into Austrian waters. The country’s best reds grow in Burgenland, about 40 miles southeast of our stop in Vienna. North of Vienna, we visited vineyards of Austria’s best-known white, Grüner Veltliner, the name of both grape and wine. Two graceful Grüner Veltliners we tasted, Lagler and Johann Donabaum, are among the many available in the United States. The grape also grows in other countries along the Danube. Among the Austrian reds enjoyed on AmaCerto and found in the United States is the outstanding Bründlmayer Zweigelt.

While most of Germany’s wine regions are along the Rhine, not the Danube, we drank its lovely Rieslings while sailing along the country’s Danube border.

Other cruises along the Danube pass other wine countries — Slovakia, Croatia, Serbia, Romania, Bulgaria and Ukraine. Each has made tremendous strides in winemaking. Each offers enticing discoveries.