Andy B.
Yelp
An all-around excellent experience at Sandeman's port cellars! Our tour guide, donning the trademark Sandeman Don's cape and hat, did a wonderful job of explaining the production and aging process, then walked us expertly through a tasting of three of Sandeman's ports - one white, one ruby, and one tawny, all quite good. The pours are quite generous so pace yourself, especially if you're going to be finishing off your friends' pours as well... I also very much appreciated the small tour size, limited at 15, making for a very pleasant, low-key experience. (Càlem, in comparison, has 40 in a group, making it feel more like Disneyland - skip them and come here instead.)
Of course, there's a nice gift shop at the end of the tour. Get a box or two of the port dark chocolates to bring home with you - just trust me on this one.
What made our visit to Sandeman extra-special was hanging out at their lovely terrace, featuring Bar George, named after one of the founders. It was a glorious, sunny 20°C day in Porto, so we grabbed a table right near the pedestrian street that runs along the waterfront and spent the next three hours or so just tallking and watching the world go by while enjoying some wonderful port-based cocktails and nibblies. The view of the city of Porto across the river and the Dom Luís I Bridge was just spectacular, a perfect picture-postcard backdrop for a great day in Porto.
I'd suggest taking a morning tour around 11 am so you can spend the early part of your afternoon enjoying the terrace, taking in the old-world beauty of Porto. Be sure to reserve your spots in advance (easy to do by e-mail), make sure you ask for a tour in the language of your choice, and get the premium tasting - just 3 euro more but well worth-it!