Is 60 min boil required for 20 min hop additions?

I have read articals about 20 minute or less hop additions to increase hop aroma and flavor, one of which is here http://www.mrmalty.com/late_hopping.htm and was wondering why a 60 minute boil is required if all of the hops are added at 20 minutes or less? Am I missing something or will this just give me darker beer and require more time? I thought boil time was set based on bittering hop additions, and with the bittering hops added at 20 mins, what would happen (good or bad) if I was to boil the wort for say 30 mins total?

You can add all of your hops late in the boil but you would have to significantly increase the amount to achieve the bittering. The longer you boil, up to 60 min, the more IBU's that will be extracted from the hop. Longer than 60 min and the utilization falls way off.

You can plug your hop additions into any IBU calc and you'll see the IBU's you get at different boil times.

The boil time itself has more to do with using grains instead of liquid extract and or DME.

You can make beer without even boiling with an all extract pre hopped kit.

On the other hand, If useing a pilsen malt, you should boil uncovered for at least 90 min to drive off DMS.

If you take the time to reseach a recipe on HBT and ask any related questions here, you will get sound advice.

Hope this helps

Bull

https://www.homebrewtalk.com/wiki/index.php/Boiling_the_Wort#The_Importance_of_Boiling_the_Wort
Using only extract and "hop-bursting" somewhat obviates the need for an extended boil.