Ray I do not remove the foil prior to the quench. I remove from oven and place between two alum. quench plates and I can pick up the foil packet in 4-5 minutes and it is down to room temp or lower. I also keep my alum. quench plates in my shop fridge-freezer that really helps the rapid cooling. 95% of my S30V blades come out of heat treatment & tempering at 60RC and every now and then I will get one at 59 or 61RC.
Just have discoloration on the steel blades and no carb buildup. Also by using Alum. quench plates, I have never had a warped blade.