Well for my third brew this past Sunday (10-10-10) I couldn't help myself and decided to wing it with a beer of my own design (though I felt pretty safe with the recipe as it was structured closely on other recipes both here and in Palmer's How to Brew and using Hopville's Beer Calculus), this is what this recipe should have been:
FG (target) 1.016-1.019
Expected ABV around 7%
Target IBU approx. 65
Five gallon batch - (three gallon boil)
5 lbs. Pale LME (boil)
1 lb. Crystal 60L (steep)
2 lbs. Pale LME and 2 lbs Munich LME - (added at flame out)
1 oz. Columbus 14.4% 60 minute (42.3 IBU)
1 oz Cascade 7.9% 30 minute (17.8 IBU)
1 oz Cascade 7.9% 5 minute ( 4.7 IBU)
(64.8 IBU total)
Note: These IBUs were calculated only on a three gallon boil gravity of just the steeping grains and the five lbs. of LME.
Things were going great until the 30 minute hop additon when I spaced out and only added .5 oz of the Cascade. I didn't catch this mistake until time for the five minute addition so I decided to add the omitted .5 oz with the 1 oz for that additon. I knew this was going to leave me a bit short of my expected 65 IBUs so I boiled for an additonal five minutes (this will also skew my other additons but I didn't think five minutes would make a huge difference other than to get me back closer to my target).
Other than the hop mix up things went well, pitched with two packets of US-05 and showed beginning signs of fermentaion at four hours, huge Krausen by the next morning and is still chugging along as expected this morning.
So, think that extra five minutes added to the boil will affect much? I guess we'll find out in six to eight weeks!