Time Out says
Here's another non-Mercè activity, but since it's on during the same time as La Mercè, why not make the most of it and include it in your festival weekend plans? On Passeig Lluís Companys near the Arc de Triomf you'll find one of the favourite festivals for locals and visitors alike: The Mostra de Vins i Caves de Catalunya (Catalan Wine and Cava tasting). From September 22 to 25 you can try wines and cavas from 66 wineries among the 12 Designations of Origin (DO) of Catalan wine. There will also be tastings of related products, such as cold meats, cheeses, dried fish, desserts, and sweet as well as savoury 'coca' pastries.
The sampling is a massive display of Catalan DO wines and cavas, and it's also an easy and fun way to get more familiar with wine culture. As with every year, you can do your own thing as you try the wines you fancy, but if you want to really get into it, you can taste the vintages during the guided presentations and tastings that are on in the big tents in the same area.
What's more, this 36th edition has a charitable side, and if you donate, you'll be giving funds to the Fundació Arrels, which, since 1987, has been dedicated to helping the homeless in Barcelona.
How does the tasting work? You 'rent' a glass for €5 (you have until 8pm to turn it back in for some money back, or you can keep it) and purchase tickets for food and drink: €6 for 5 tickets; €13 for 12 tickets; €20 for 22 tickets. Salut!