90 vs 60 min Boil

What does a 90 min boil do other than drive off dms? Could it help form a maltier backbone in beers....IE would doing a 90 min boil be a good idea for a beer you want to be malty.

A 90 minute boil also reduces the volume so you can collect more and boil down to get a higher efficiency, and will also increase the IBU of the final product.
I think there is also something about driving off more DMS as well.

The Answer is explained here!

It drives off more DMS, leads to higher IBUs (given the hops are in the whole time), higher OG (cuz less water), and causes more malliard reactions leading to darker wort and more caramelization.

Arkador: I've seen that said before, but why would a longer boil have anything to do with a higher efficiency? Once you get above 170F there's no longer any enzymatic activity so boiling longer shouldn't effect efficiency.

dcp27 said:

Arkador: I've seen that said before, but why would a longer boil have anything to do with a higher efficiency? Once you get above 170F there's no longer any enzymatic activity so boiling longer shouldn't effect efficiency.

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I think Arkador is referring to collecting more wort during sparging. If you have to stop collecting wort because you've run out of room in your boiler, you will have a lower efficiency. The more you collect, the more sugar in the boiler. But the longer you have to boil to get back to your batch size.

pkeeler said:

I think Arkador is referring to collecting more wort during sparging. If you have to stop collecting wort because you've run out of room in your boiler, you will have a lower efficiency. The more you collect, the more sugar in the boiler. But the longer you have to boil to get back to your batch size.

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Oh OK, if thats the case for the longer boil than that makes sense. I was thinking same pre-boil conditions in both cases and all that was different was the boil length.

I like to collect 7 gallons from the MLT, and boil for 90 min to get to 6. I'm on a stovetop doing all grain, so I can't drive off 1 gallon in just 1 hour. I usually don't start hopping till 60 min left, so my IBUs are right, for reasons stated above.