About a year or two ago (I looked/ searched and can't find the original thread) someone was asking how to get more crem on the top of coffee. I think I've found the answer by accident. I have a programmable coffee maker which grinds the beans immediately before brewing a pot of coffee. It broke and I've been manually making coffee. I find that if I vary the temperature of the water, the amount of crem varies relative to the change in water temperature. Water boils at 100 degrees C = 212 degrees F. If you boil water prolonged all the oxygen escapes. Colder water has a higher concentration of oxygen. I see the most crem around 99C or 211F meaning right as the water begins to want to boil, but not a full boil. By definition water boils when the surface tension breaks. To get to this optimal temperature bubbles willl start coming from the bottom but not breaking the surface. I do this in a glass saucepan. So if you want max crem on your coffee and you can control the temperature at which the coffee "brews" you now have something to start on. Play with the temperature and watch how much crem you get on your coffee. It's interesting.