90 minute boil

Hello all I am about to brew a big RIS and it was suggested to do a 90 minute boil. When adding the hops should I start at 90 minutes or should I boil for 30 minutes and then add my battering hops at 60 minutes.

TIA

I just did my first 90 minute boil...pumpkin ale 8%, and i had hops in for the full 90 minutes and it finished quite nicely. I dont know if there is a hard fast rule on it, but just wanted to share my success with having in for the full boil

Unless you have a 90 minute hop addition (rare), then add the hops at the times you normally do, usually starting at 60 minutes.

Why are you doing a 90 minute boil, exactly? What was the reasoning behind it?

I can think of only a few reasons to do a longer boil:

1. Using Pilsner malt (don't think that is the case here)
2. More hop utilization
3. To carmelize the wort more for flavor/lower attenuation purposes

If none of these fit what you are trying to do, then just use a 60 minute boil and save yourself 30 minutes on brew day.

If you still plan to go ahead, and the recipe is written for a 60 minute boil, then you should make adjustments to your pre-boil volume to compensate for the additional amount that will boil off during that 30 minutes.

Thanks yooper. Weirdboy I am looking for better utilization.

Utilization differences between 90 and 60 minutes are negligible. Do whatever feels good to you

Hop utilization is negligible but 90 minute boils will boil off more water and more water through the mash will increase mash efficiency if your doing all grain. With large grain bills it can be helpful. It also changes flavors. I did no sparge and a 120 minute boil on my last strong stout it it was loaded with many complex flavors.

What should I do then, longer boil or add more hops. OG should be around 1.117

Personally I would just add more bittering hops.