Scorched extract :(

So my spoon wasn't long enough to reach the bottom of my 7 gallon boil kettle and I ended up burning a good portion of extract on the bottom of the kettle. How is this going to effect my final product? The beer was a Holiday Spiced Ale from Midwest, if that makes a difference.
Also, I was just reading the This vs. That FAQ and it said that CIP cleaners shouldn't be used on aluminum but PBW says that it can be. That's what I ended up using to get the scorched extract off the bottom of my kettle. Have I really done major damage?

your beer will probably have a burnt taste to it. How bad?? Only time will tell.

That's sort of what I figured. I will have to wait and see. Hopefully the spices in the recipe will mask the burnt flavor. Anyone have any ideas about why CIP cleaners shouldn't be used in aluminum?