Need some help with an Oktoberfest

Ok, I want to brew the Oktoberfest from "How to Brew". I already bought the ingredients and after checking with Beer Recipator it comes out too dark (17 SRM). Here is my little dilemma. The recipe is a partial boil and I want to brew a full batch and the guys at the brew shop didn't have Pale Malt Extract (LME) but they had Pilsner Light (LME) and Munich LME. They insisted that I use the Munich so I bought 2 3.3lbs cans of Munich and the rest of the ingredients.

I just wonder how can I tweak the malt extract to get it somewhere close from 7 to 14 SRM?.

Does a full boil changes the color that much?

How about steeping the grains efficiency? is 40% the right percentage to put in the Beer Recipator?. Beer Recipator asks for the percentage and they say 40% is the norm so that's what I wrote there.

The Preboil is 6.25 gallons and I want to end with about 5.5 gallons or even 5.25 gallons. 50 min boil.

The recipe calls for:

3.3 lbs pale malt extract in boil (I have Munich)
3.3 lbs pale malt extract at knockout(Munich)
0.5 lb CaraMunich
0.5 lb crystal 80L malt
1 pound Munich malt
1 Oz Tettnang (the one I bought is 4.8% AA)
1 Oz Liberty ( the Oz I got is 4.3% AA)

Tweaking the hops boiling times gives me 25 IBUs just like in the recipe though.

Any help I'll appreciate it. Thanks

Assuming the Munich extract is really only 50% Munich and 50% Base Malt the shop gave you good advice.

If you want to lighten the color you could look at dropping the crystal 80. I would bet the LME will finish plenty high that you could easily make the sacrifice.

You could do a partial boil. I don't even think about doing full boils these days with extract. I would do your partial mash with the Munich malt and use that wort for a 2-2.5 gallon boil and add all the extract the last couple minutes. Your hop utilization will go down because of the smaller volume but you avoid darkening the extract.

agreed, drop the crystal....you don't need any crystal in a Oktoberfest.....if you want to keep the amount of grain in the bill, exchange it for vienna or munich malt.......that will give you better flavor than the crystal and the lovibond isnt as high as the crystal so your color should come down

the problem with the color is the extract.....extract, the color is hard to control.....you kind of need to accept that you are going to be darker than usual.......also most your beers will be close to the same color.......it wasn't till i switched to AG that the colors started being more accurate.......

Thank you guys,
I'll try the partial boil then. Next time I'll drop the Crystal 80 and get either more Munich or some Vienna malt.

Thanks a lot.