Let the apples simmer until soft. The amount of time it takes for the apples to get soft is dependent on how many apples you use and the level of heat used. I usually let the apples simmer for a couple hours, stirring every 15-20 minutes. The softer the apple, the easier it goes through the food mill, and the greater the yield. I have found that if the apple isn’t completely soft, there is more waste.