Technically you can't get the wort hot enough to carmelize (Maltose carmelizes at 356F). Reducing sugars undergo Maillard reactions (sugar and amino acid reaction) when heated and this causes darkening. Doing full boils minimizes this. Adding extract at flameout or very late in the boil also minimizes these reactions. The classic flavor threshold for diacetyl (the primary VDK) is about 0.15ppm but in an ale there are a lot of things that help mask it and as homebrewers I do not know how low we can get this number from a practical standpoint.
You should also steep in less water (about 2 qts per pound of grain) to prevent astringency. You can do this on the stove top or in the oven (lowest setting for about 30 minutes once up to temperature).
Something is always fermenting....
"It's Bahl Hornin'"
Kegged: Sour Saison, Pale Ale, Aggie Ale, Firestone DBA, De Koninck Blonde
Bottled: Belgian Quad (Grand Reserve), Derangement (Belgian Dark Strong)
On Deck: Pliny the Younger