Imperial IPA, IBUs and taste

[bosox]

I think I'm going to make a real Imperial IPA. I've got 3 oz each of Centennials and Amarillos for taste/aroma and some 2 oz of Magnums for bittering, but here's my question. Using the BrewBuilder by Brewmasters Warehouse (I think?) I can seem to get my IPA up around 80-82 IBUs easily, but with low alcohol content using just 6 lbs of DME. So I try adding a few lbs of grains, as that's all I've ever brewed with before (partial mashes) but my IBUs drop significantly, and my ABV is only around 6.9%.

As I'm only making 5 gallons, it sounds like it would be too much for me to be using 5, 6, and 7 lbs of grains with 6, 7 lbs of extracts, and then having to add more ounces of hops. I already had a recipe with 6 oz of hops, 6 lbs DME, and 3 lbs of a smoked malt, but that was only 77 IBU and 6.9% ABV....
I'm aiming for something near 90 IBU, with around 8-9% ABV. Something like Publick House's LARRY

How would I go about doing this? Sorry if it's long

 

[mightynintendo]

IBUs have an inverse relationship to your OG. These numbers don't sound out of range at all.

 

[zodiak3000]

doing a late extract addition will increase your hop utilization, aka give you more ibu's when adding most of your extract the last 15min or end of boil. i dont remember how much it increases, but do some research on the forum or google it, or if you have beersmith you can find the option on there that will give you the exact ibu's just adding malt extract vs. late extract addition

 

[carnevoodoo]

3 pounds of smoked malt?!

 

[dsabra11]

I just did an IIPA today but did not realize that doing a 3gal boil and then diluting it to a total 5 gallons would drop my IBU level from 113 to about 56. Is there anything I can do, post-boil and post-pitch, to increase the bitterness of my beer? Will it still taste like an IIPA or will it be more like a barley wine? How will dry hopping affect the overall flavor. This was an all-Centennial hopped 120 minute boil extract IIPA. Thanks!

 

[dcp27]

doing a late extract addition will increase your hop utilization, aka give you more ibu's when adding most of your extract the last 15min or end of boil.

+1 to the late add. Also, how big is you boil size cuz that makes a huge difference? 6lbs grain, and 6lbs DME with half the DME late would get you 8-9% ABV and around 90IBUs in a 5+gallon boil with just the magnum alone. You may also want to replace some extract or grains with sugar added late to help dry it out.

 

[dsabra11]

boil size was 3 gallons. I have a 5 gallon pot, but need some room for the DME, etc. I did do some late adding, I did half to start, and then the other half later on. That probably didn't make much of a difference since the extract was already in there. Too late now, but next time I will know better. Live and learn (just like that beer explosion I woke up to today... I guess with higher grav beers, you get more krausen and 5 gal in a 6 gal carboy is just not enough room.)