What are the benefits of the 60 minute boil if I plan on doing my bittering addition at 45 minutes. Actually boil time would be closed to 50 by time the hot break drops then hops added at 45.
I think you will be fine with a shorter boil. 45 or 50 minutes no big deal without the DMS/pilsener malt thingie.
Nothing really. Slightly more boil-off, so you might have a slight efficiency gain from sparging with a bit more water. Probably won’t be measureable, though. Some under-modified malts may have some issues with DMS with only boiling for 45 minutes, but I think you’d have to go out of your way to find those malts.
The reason I ask is I plan on using dual purpose hops for bittering and would like to get a little flavor from them also. I have quite a bit of Chinook to use up.
From what I understand is your not going to really get much flavor and aroma from hops in general when boiled for that long anyways. Bittering hops additions are boiled for 45-90 minutes to isomerize the alpha acids; the most common interval being one hour. There is some improvement in the isomerization between 45 and 90 minutes (about 5%). Aroma and flavoring hops are used between 40 minutes to the end of the boil, 30 minutes being most common to start due to the flavors and aromas boiling away at longer times. In my opinion, your going to get your bitterness from those hops, but may not get the flavor and aroma your looking for at 45 minutes.