I'm playing with a DIPA recipe I'm brewing tomorrow, but the boil gravity estimate is confusing and worrying me. The recipe is http://www.brewersfriend.com/homebrew/recipe/view/62146/pliny-in-dumnonia. I can't see how I'm going to reach my OG of 1.072 when the boil gravity is only estimated at 1.049. Doing the maths, 27.2L of water in the kettle x 49 pts = 1348 pts. Divide that by the volume at at the end of the boil (so the only thing to subtract here is boil off - 5L) = 1348/22.2 = 1.060. I'm quite worried that I'm not going to hit my OG target... Am I being an idiot?