What went wrong with my tripel?

Last weekend, I made my first tripel. Although I formulated the recipe on Hopville, which predicted that the beer's color would be 6 SRM (yellow-gold), it actually ended up being about 15 SRM! Does anyone know what would have caused this? Does boiling the sugar or malt for a long period of time make the wort darker?

Fermentables
8 oz. Crystal Malt - 20L
4 oz. Carapils
2 oz. Belgian Aromatic
7# Extra Light DME
1.5# Sugar in the Raw

Hops (whole)
2.5 oz Saaz (3.9 AAU) @ 60min
1 oz Tettnang (3.4 AAU) @ 60min
1 oz Tettnang (3.4 AAU) (3.9 AAU) @ 30min
2 oz Saaz (3.4 AAU) @ 30min
1.5 oz Saaz (3.4 AAU) @ 5 min.

Steeped the grains at 150 for 30 min. 90 minute boil w/ 3 gallons of water.

Yeast
WYEAST 3787 - Trappist High Gravity (w/ 2L starter)

Misc.
1 tsp Irish Moss @ 15min

Any thoughts?

Does boiling the sugar or malt for a long period of time make the wort darker?

Click to expand...

Yep!

Did you boil all 7#'s of DME for 90 minutes in 3 gallons of water? If so that's probably why it's darker than expected. That's a pretty concentrated wort to boil for that long.

I plan on brewing my first tripel tomorrow based on the recipe from "Brewing Classic Styles." It calls for 10.5 lbs of LME. Since I'm brewing on my stovetop I'm using half the extract and adding the rest at the end of the boil, in the hope of keeping the color light. Even though I split the LME it will probably be darker than expected because I'm using 5 lbs in a partial boil. We'll see how it turns out...

Yes a 90 minute boil will darken the color due to caramelization. Also when calculating make sure you specify your boil volume was 3 gallons.
Using the brewers friend srm calculator http://www.brewersfriend.com/srm-calculator/ I get 12 using cane sugar. They dont have sugar in the raw as an option. Using Belgian candi sugar (amber) brings it up to 24. That assumes a 60 min boil I'm pretty sure.