Tried to do my first DIPA but came in at an OG of 1062 instead of 1070. I guess it was the additional half gallon of wort that I produced which thinned it down and brought down the OG. I had planned to strain the 5 oz of hops that went into the boil, but that proved impossible, the srainer got clogged with hop matter and I ended up just throwing out that greenish 1/2 gallon of wort.
Making a DIPA makes me better understand why those suckers are so expensive, lots of malt and lots of hops, and that’s that I used about 30% less hops than Pliney. Ultimately, it looks like a made a big IPA but not an imperial pale ale.
BTW 1.070 is a bit too low for a DIPA gravity-wise. You should try to get your OG above 1.075 (I prefer 1.080 and above) and your IBUs should be above 75 (or 100, what the hey!). When using a crapload of hops, I usually use hop bags, they just make it easier IMHO.
I was working off of the Pliney recipe in Zymurgy which had an OG of 1070. Prior to seeing that recipe I was under the assumption that IIPAs were all above 1080.
Given how many factors tend to reduce the bitterness of a beer compared with its paper IBU’s - hop age, whole hop floating, and boil vigor being the main ones - I never concern myself with my calculated IBU’s being 10-15 over the limit for a pale ale or IPA. With an DIPA I also would shoot for 1.080 or so, but I actually prefer a big AIPA over a DIPA, so for me the IPA “sweet spot” is about 1.070-1.075 and 70-90 IBU - technically that’s DIPA territory, but I don’t think of it as such.