If one were brewing an extract version of an IPA without any bittering hop additions, is there any advantage to boiling longer than say 15 minutes? 15 minutes seems to a recommended time in order to kill off any bacteria.
Great question. No, there is no advantage. Personally, if I were you, I would only boil for 10 minutes, which is plenty enough time to kill wild organisms.
Enjoy!
Thanks.
There is one advantage of boiling for X time: if you know your boil off rate, you will hit an expected specific gravity. If you boil less time, you won’t hit your specific gravity. If you’re ok with that then… there ya go.
If he’s using extract I don’t see a problem. You won’t lose much in a 15 minute boil so you can start with pretty much your finished volume.
If all you are looking to do is pasteurize, you don’t need to boil at all. You just need to reach 160F. By the time you reach this temp, all microbes of brewing concern will be dead.
Not planning a full volume boil anyway as my friend only has a 5 gal pot.
i tried creating a super short brewday method i could use where it was cold-steeped specialty grains (passive time 12-24 hours before brewday), then all extract and a 20 min boil with a lot of hops at 20 and on down to 0.
it could have been my own personal failure to do so, but it did not make a very good beer, it severely lacked bitterness and flavour.
maybe others have a good ~15 min boil technique, and for sure try it out, but thats my experience. it could have been many factors at play.
Sounds like the OP is using hopped extract so bittering shouldn’t be an issue. When I was developing my 20 min mash/20 min boil technique I found that doubling the bittering hops got it where I needed to be. Late additions is were not altered.
Due to circumstances I’ve been using mostly extract for a long time and boil anywhere from 0-20 minutes with good results.
I recently did a BIAB stout for the first time and it came out good with a 20 minute boil.
I find all posts/replies most interesting. Thanks to all. Guess I’ve been an all grain brewer too long and forgot about the extract short boil 
I’ve thought about this, too. Rather than risk boiling-off the hops put in by the maker of the pre-hopped extract, I’ve decided to just bring the wort to a temperature a little short of boiling and keep it there for about ten minutes. Water boils at 204 degrees F where I live, so I’m thinking 195 degrees F would do the job.
Yep. Even 165.
That’s the same temperature we very often see to which to heat things we’re going to eat. Heating to just 165 - 170 would provide a good cushion against scorching…