Are reservations available and recommended? Visiting Vienna in early August and would like to go to one of these dinners.
From the Vienna section of this website:
For another royally good experience, head to the Heurigen (wine gardens). Clustered around the edge of town, at the start of the legendary Vienna Woods, wine-garden restaurants feature cold-cut buffets paired with fine Austrian wines in an old-village atmosphere with strolling musicians. If you visit in fall, try Sturm, the semi-fermented new wine made from the season's first grape harvest and only available in autumn. Many locals claim that it takes several years of practice to distinguish between Sturm and vinegar. The red version is so hearty and fruity that locals say "Eat up!" when toasting with it.
Of the many wine-garden suburbs, Grinzing is the most famous and lively. To avoid tour groups, try Nussdorf, popular with Viennese. Music lovers head to Heiligenstadt to visit the Beethovenhaus wine garden, where the composer lived and began work on his Ninth Symphony.
Are reservations available and recommended?
Yes and yes. Reservations are not absolutely necessary, but on a warm August evening most Heurigen will be packed with people.