This barebones machine has a simple function button that toggles through four options: cold foam, hot with light froth, hot with heavy froth, and hot without froth. Pour in 8 ounces of milk, which is the recommended maximum for the unit, then pop it on the base and choose one of four modes: cold froth, hot with no froth, hot with light froth, and hot with heavy froth. I did this three times with each frother and made note of the average time of its frothing cycle, the final temperature of the milk, and the consistency and texture of the frothed milk.