If you are looking at this just do it. This is the best thing we did in Barcelona! Awesome half day experience. This is such a great way to enjoy Barcelona. Sailing along the coast and then enjoying wine tasting at a small vineyard. If you are thinking about this here is what you should know:
First thing that may not be obvious is where do you meet the boat. When you arrive at the docks look for an orange and blue tent that says BDA. In front of it are several sailboats and your captain will be there looking for you. Say hi and hop onboard.
The sailboat is large enough to accommodate 8 people comfortably. It has a bathroom (head) down below. You can sit up at the front of the boat if you like or in the back on the benches with a nice table between. The captain has music playing and offers a tray with various cheeses, olives, crackers and cured meats. He also offers wine, Cava, and beer.
The trip takes a little over an hour up the coast. It is beautiful and relaxing. Obvioulsy the weather can vary greatly, but assume that it will be 10' colder on the boat than the shore, so bring an extra layer if it is a little chilly outside. You can always go down below inside the boat if needed, but you probably wont want/need to. The captain is very nice and hospitable. Don't expect a sightseeing type tour here with explanations of landmarks or history... this is a relaxing sail. The sail ends at another dock in a small town at the edge of the mountains. From there a nice van will pick you up and take you for about 10+ minutes to the vineyard. Don't forget to tip the captain.. while tipping is not required for most of Spain, note that the tour guides and captains do appreciate tips.
The winery was Bouquet d'Alella. It is an old small winery. It is big enough to produce some amazing wines, yet small enough to be able to still provide a complete tour of the vineyards and wine making process. This is much better than a typical winery tour in Napa which is more about selling you bottles than really seeing the winery. Here we went for about an hour tour of the vineyards, processing and cellar. Our guide/host was very knowledgable and really gives you a complete education of Spanish wines. You will learn a lot. But she was always engaging and never boring.
After the tour we sat outside around these beautiful tables under a pergola overlooking the vineyard and the coast. Just an amazing setting. We tasted 4 wines: 2 whites (Blanc and Blanc+) and two reds (Granatza Negra, and Syrah). All of them were really good.. nothing got poured out by us. The whites are of the same grapes but each has a distinct tasting profile as one is aged longer and they have slightly different percentages... all of which your host explains and helps you taste the subtle differences. The reds also were fantastic. Our favorite is was the Syrah, which for the price is just a killer bottle of wine! I also asked to try the Cava and it too was great. We ended up ordering a half case and having it shipped back to the states. Even with the cost of shipping, it was still far cheaper than buying similar quality wines at home.
During the tasting you are also given a loaf of fresh local bread, fresh tomatoes, some cheese and cured meat, along with olive oil. This was perfect to enjoy while sipping the wines. Note that this is a wine tasting, so while you wont get 4 full (6oz) glasses of wine, you do get 4 generous tasting pours (about 3+ oz) to enjoy. We never felt rushed, the timing was perfect. Once finished the van took us back to the dock in Barcelona. About a 30 minute ride.
A few last minute notes: The winery has nice and clean restrooms. You may want to make sure you have breakfast before the trip. While there is plenty of "snacks" throughout the sail and wine tasting, it is not a meal. Almost everything is outside so dress accordingly. While not a lot of walking, you will want to wear comfortable shoes. If it is sunny out, you will probably want sunscreen. Try the Cava on the sail and at the winery.
This ended up being our favorite experience in Barcelona. An enjoyable relaxing day experiencing Spain.