Diacetyl or too much corn?

[hoplobster]

I bottled my Cream Ale last week and it's carbing nicely but I can't tell if I made an error either by not being through in my sanitation practices and introducing an infection or by adding too much flaked corn to my recipe.

Flaked corn made up about 8% of the grain bill and I know it's only been a week since bottling, but does anyone have any thoughts? I'm thinking the corny/buttery flavor is due to the corn (my first attempt using such an adjunct) and it will probably become more subtle with aging.

4 lb. German Pilsner
.75 lb. German Vienna
.50 lb. Dextrine malt (Cara-Pils)
.50 lb. Flaked corn
.50 lb. Flaked rice

.30 oz. Perle (7.6% AA, 60 min.)
.25 oz. Hallertauer Hersbrucker (3.3% AA, 30 min.)
.50 oz. Saaz (3.5% AA, 30 min.)
.25 oz. Hallertauer Hersbrucker (3.3% AA, 5 min.)
.25 oz. Saaz (3.5% AA, 5 min.)
.25 oz. Saaz (aroma)

WYeast 2565 Kölsch Yeast

 

[Beerrific]

Could it be DMS? Pilsner malt contains DMS precursor and is converted to DMS at temps above 140, when boiling it is driven off so cooling from boil to 140 fast is important.

I used pilsner malt in my Kolsch and hefeweizen. Until recently I could taste a slight corn flavor...but it has definitely subsided.