Using late hops only

[Ciderhead]

I use the tool in beersmith. The higher your starting gravity the higher the abv.

[mr hoppy]

My understanding is that the 90 min boil recomendation referenced above is more relevant for pilsner malts which have more DMS precursors than for pale malts.

[DEMPSEY]

If I were to use a load of hops for the last 15 minutes of a boil (i.e., no 60 minute bittering addition), is there any point in boiling longer than 15 minutes? I could even use the FWH technique if I wanted to and still do a 15 minute boil?

I think you are missing the reasons why you need to do a boil.
If you only put hops in at the end of boil then you miss out on what they do if put in at the beginning.The low pH and the antibacterial action of certain hop constituents will ensure that the pathogenic and spore-forming organisms that would otherwise survive are precluded. The remaining enzymes that did not get killed during the sparge need to be murdered in the boil so this fixes the carbohydrate composition of the wort, i.e. maltose stay as maltose and dextrins stay as dextrins . The raw wort is full of proteins and other polypeptides as well as polyphenols or tannins ye want them to get so sticky they clump together and fall out of the wort.
The DMS issue is another factor and while some beer styles want some others don't so the question of time for a boil I would say 60 minutes covers all of the above even though most of it will probably happen after 15 minutes of boiling.

[delzep]

If I were to use a load of hops for the last 15 minutes of a boil (i.e., no 60 minute bittering addition), is there any point in boiling longer than 15 minutes? I could even use the FWH technique if I wanted to and still do a 15 minute boil?

I think you are missing the reasons why you need to do a boil.
If you only put hops in at the end of boil then you miss out on what they do if put in at the beginning.The low pH and the antibacterial action of certain hop constituents will ensure that the pathogenic and spore-forming organisms that would otherwise survive are precluded. The remaining enzymes that did not get killed during the sparge need to be murdered in the boil so this fixes the carbohydrate composition of the wort, i.e. maltose stay as maltose and dextrins stay as dextrins . The raw wort is full of proteins and other polypeptides as well as polyphenols or tannins ye want them to get so sticky they clump together and fall out of the wort.
The DMS issue is another factor and while some beer styles want some others don't so the question of time for a boil I would say 60 minutes covers all of the above even though most of it will probably happen after 15 minutes of boiling.

So a 15 minute boil is enough so

[DEMPSEY]

When I say most in 15 minutes does not mean all . Good practice is to boil a minimum of 60 minutes to kill all the lurgeebeans.