PLEASE HELP! Need help with pre-boil gravity ASAP!

Hey guys, brewing an imperial white now that I am aiming to be a gravity of 1.092. I did a pre-boil reading for the first time and when aiming for 5.5 gallons, the equation gave me 5.75 gallons. What does this mean and what should I do?! Any help is VERY MUCH appreciated!

You could turn up the burner so your evaporation rate is higher to burn off the extra .25 gal.

If needed, i have a reading of 1.071 with 7.5 gallons. Plan to boil 2 hours down to 5.5 gallons and want to hit 1.092

My first hop addition is at 60 minutes and boil is just starting now. I have an hour to correct anything so any help would be appreciated.

@brettg, i will just boil for another 15 minutes since my evap rate is set at gal/hr. is there anyway for me to make up for that .25 gallon though? Or is it really not worth it and just be happy with 5.25 gallons?

Also, if I wind up boiling for an extra 15mins and wind up with 5.25 gal instead of 5.5, how would this affect IBUs?

You are going to have a slightly higher IBU if your boil is a little longer due to the fact that your later additions will be recalculated. Instead of a 15 min addition, it would be a 30 min addition and so on.

Nothing detrimental... every brew is an experiment.

@VTrookie, there are no later additions for this beer, only spices added at 5 mins. How would I account for this in beersmith? I figure that I will change my batch size to 5.25 gal, change the efficiency accordingly, and then keep everything else the same (boil an extra 15 minutes and still add bittering hops with 60 minutes left + spices with 5 minutes left). Would this effectively tell me how my beer is going to come out? thanks for your help guys, continued insight is definitely appreciated!!!

@brettg, according to what i just read, you are thinking backwards. I am over efficient so should boil less? According to this equation that is quoted below, instead of a 1.092 OG at 5.5 gal, I will wind up with 1.098 at 5.5 gallons. Here is what I found and read:

"Then using your gravity, volume and expected boil off you'll be able to calculate your expected SG. For instance if your preboil gravity is 1.050 and your volume is 7 gallons you have 350 gravity units[(GU)= 50x7) if you expect to boil down to 5.5 gallons you can devide the GU into the 5.5 and get your expected SG (350/5.5=63) for a starting gravity of 1.063 if you boil down to 5.5 gallons."