Bittering hops

Still very new to this, but I was thinking, does it really make a difference what bittering hop you use? Shouldn't the only thing that matters be the ibu? Technically aren't you boiling out all the aroma and flavor? I'm sure I'm wrong but could someone explain this to me.

Like a lot of questions in homebrewing the answer is, it depends. While CW says it doesn't matter IMO it does. Even though the bittering hops don't yield as much direct flavor as later additions there is an influence on the beer's hop flavor from them. To keep it simple I would suggest to use bittering hops that are in the same general family and compliment any flavoring hops used in the beer. As examples, for an American style ale bitter with Columbus and flavor with Amarillo, for a British style ale bitter with Challenger and flavor with Goldings. Since these hop pairings share some general characteristics you would be certain of a good flavor blend within the beer. There are endless combinations and you can certainly use whatever you like but when starting out keeping things simple is probably a good idea. From the link below you can click on the pdf for Hop Union's Hop Variety Listings to see descriptions and suggested uses of dozens of different hops.

http://www.hopunion.com/hopeducation.html

There are six major alpha acids and six beta acids. Each hop has a different mix.

I use Columbus much of the time.

I am inclined to believe that bittering hops impart some kind of flavor onto the beer, although it is not being used for "flavor."
Otherwise, every brewer would just use a really high alpha acid hop and add as needed to achieve a targeted IBU. Why would a brewer use 3 oz at 5% aa, when they could use 1 oz at 15%?-

Just guess- but it would be nice to have a definitive answer

It's what david 42 said (like 8 months ago...), different hops have different ammounts of alpha and beta acids. I believe beta acids contribute a "harsher" bitterness, and alpha acids a "smoother" bitterness, but I'm sure it's far more complicated than that.

I'm pretty sure BMC uses tiny amounts of super-high alpha hops (you know, to cut down on cost), whereas traditionally European lager brewers would use larger amounts of super low-alpha noble hops (cuz that's what they had).

you don't lose ALL flavor in a 60 minute boil