OK, there is one kinda secret ingredient. It’s something that nearly all commercial ice cream makers use. That’s skim milk powder, or nonfat dry milk powder. Sounds fancy, but really it’s just dehydrated milk. Ice cream makers use it to combat the effects of too much water in their ice cream base. Milk is almost 90 percent water, and heavy cream is about 60 percent water. You need water to freeze your ice cream, but too much water will freeze into itty-bitty ice crystals … and your ice cream will be icy and grainy, not smooth and creamy. Skim milk powder absorbs excess water and gives a milkier, creamier flavor.