Tasting Notes, and what to look for

Maybe the title isn't exactly right, but I'm sitting here drinking a Chimay white label and I'm confused. Getting into homebrewing taught me that there is a lot to know about homebrewing. I used to be a chef, so I thought that would help, but it doesn't at all. When you eat something, you have the advantage of seeing what it is that you're tasting, so if you like it, you go buy it. Drinking beer is quite a different animal. Maybe it's my inexperience as a beer "taster". I say taster because I used to drink a lot of different kinds of beers, but never actually tasted any of them. I drank them with one goal: get drunk. Now that I brew my own, I drink beers to taste them. Gone are the days of figuring out how to get the most beer for my money, and how to get drunk as many times as I can with a 30 pack.

So this is my question. How do I know what I'm drinking? I'm drinking this Chimay and besides each sip smacking me in the back of the head, it's making me think "What is that I"m tasting?" So I'm wondering if there's a written source of what flavors go into a beer, or better yet, a commercial beer. I've often wondered what the back flavor in a Blue Moon was. I read about beers having grapefruit notes, or plum notes, or banana notes....with all these notes, is there a written note about what it is? is it cheating to try to find what I'm looking for, or do I have to experiment on my own to try and find the answers? Basically, I want to be able to drink a beer and figure out what all these notes are that I'm tasting. Is there something to tell me this?

I just picked up "Tasting Beer" by Randy Mosher today after thinking the same thing a few times.... 'course I haven't read it yet.