For my personal take on Belgian brews see, after the race: Belgian Beer. Here I want to focus a bit more on where you get the liquid gold. As I mentioned in my earlier post, most traditional Belgian beers are rather delicate and don't travel well. They need to be taken care of and such special care can only be provided in special places. If you wanted to skip the bars altogether and buy beer to consume at home, be advised that local brews are also hard to find. You could easily visit a dozen grocery stores (beer is sold in grocery stores in most places) and never see one. Even specialty liquor stores may not have them, focusing on wine and spirits instead.
Your average neighborhood bar, called a cafe in Belgium will only have a limited selection of beers. Furthermore, they may not be very brand conscious and just serve you what they think is a regular beer, or a more fancy upscale beer, or even a Trappist, regardless of what and how you order it. Truth be told, with the large influx of tourists, most places in bigger cities and tourist hangouts will usually ask you if a substitute beer is OK. But it is not like you will have much choice.
Fortunately you can get a decent Duvel anywhere in Belgium. That is another reason why I like this beer so much. You don't have to go out of your way to get it.
Contrary to what you might think, tourist hangouts are to be avoided. If you want to go there, go there for the sights and sounds, but don't expect the really good stuff. Also expect to pay through the nose for whatever it is you order. Some places, like the Markt in Brugge simply focus on charging the highest price for whatever item, while others, like the Markt/Grand Place in Brussels, seem to specialize in serving odd looking contraptions that make foreigners pause. One such contraption is Kwak, a fairly decent brew that comes in a special glass that attracts tourists like honey attracts bears.
While tourist hangouts may serve Lambic, Kriek, Cassis, and Peche, all of it will be artificially sweetened stuff -usually from Lindemans. Not that that is necessarily bad, and I too enjoy a Kriek after riding up the Kapelmuur in Geraardsbergen, even if it isn't the real thing. The exhaustion and the setting take care of that and any Kriek I have had in Geraardsbergen has tasted as good or better than the real thing.
When riding remember to visit the Cafe of the Ronde Centrum in Oudenaarde after your ride and taste the Flandrien on tap. The Ronde Centrum is an ideal spot to start and end all your rides because all the major tourist routes originate and end here. Here you can access the blue loop, the green loop and the orange loop I mentioned before. You can also take a shower and use the facilities before indulging in some local brews. The cafes on the Markt in Oudenaarde are more scenic, but the Flandrien is a beer worth trying and you can only find it here. Plus you can buy the glass with the bicycle wheel on it.
That said, to drink the real thing, go visit a bierkroeg or streekbiercafe. Some are easy to find and easy to get to. That is the case with Herberg De Dulle Griet on the Vrijdagmarkt in Gent or the nearby De Trollekelder by St. Jacob's church. Also in Gent you can find good food and excellent drink at Brasserie Deus in de Vlaanderenstraat.
Cafe de la Paix on the Grote Markt in Poperinge has a great selection of both speciality and regional beers but you will probably want to drive there. As the Michelin guide would say, it is well worth the detour. On sunny days there is a nice outdoor area where you can sit and watch the townspeople go about their business.
In Bruges, your best bet is 't Brugs Beertje in the Kemelstraat. That is easily accessible and close to the underground parking 't Zilverpand.
There are many excellent bierkroegen in and around Antwerp and Brussels but to go there you will probably need a car. If you go in summer and race the kermis races of Hoeleden-Dries near Leuven, be sure to make a slight detour and visit the town and brewery of Hoegaarden. You should also go by Leuven. Leuven is a wonderful town with beautiful buildings and if you have time to spare you can visit the Stella brewery there.
Finally a tour of the Lambic area in the Zenne/Senne valley, Southwest of Brussels is a must for the true connoisseur.