Miele DGC6500 Operating And Installation Instructions page 56

Steam Cooking
Cooking duration
Tips
56
The cooking time depends on the thickness and consistency
of the food.
The longer fish cooks, the firmer its flesh will become. Use
the cooking times given in the table.
If you find that the fish is not cooked sufficiently, cook it for
only a few more minutes.
When cooking fish in sauce or stock, we recommend that you
increase the indicated cooking time by a few minutes.
Cook larger fish on its belly (swimming position). So that you
get the necessary stability, place a small cup or similar item
upside down in the cooking pan. Set the fish with the opened
belly side on that.