Steaming and frothing milk is a fundamental skill every coffee barista must learn. It takes time to learn, and mistakes happen along the way. The steamed milk and milk foam are used to prepare flat whites, cafe lattes, cafe macchiato. Let us learn the difference between wet and dry cappuccinos.
Steamed and frothed milk
It takes time in trial and error to learn to steam and frothing milk. Once you understand the logic in the components in milk, brewing becomes easy. Milk has three components that change to water vapor through the steam wand.
The composition of milk
Proteins – about 3% of milk is proteins. Protein in milk is divided into whey and casein. Casein protein is about 75% of the milk weight. Its molecules suspended in the whey water-soluble protein. When milk is steamed, hot vapor forces into casein molecules and reconnect around air bubbles. Foam is formed by the trapped milk bubbles to make the milk thick and creamy. The casein proteins hold air, and it contributes hugely to the curdling of milk. At 180 Farads or 82 degrees Celsius, casein proteins no longer hold together, making the milk scald.
Fats – milk contains about 3.5% butterfat. Fat contains about 400 types of fatty acids and glycerol in one molecule. Heating the milk weakens the bond between fat molecules and make them move around. When fat molecules distribute throughout the milk, milk achieves milk/silky taste and forms a firm foam. Baristas barely use whole milk, but the 2% skim milk has enough fat to make the texture and foam. Studies from the University of California show that milk with high fat stabilizes better at temperatures below room temperature, and milk with low-fat content is much stable at high temperatures.
Carbohydrates – carbohydrates in milk is called lactose and constitutes 5% of milk volume. Lactose is made of glucose and galactose sugars combined. Frothing and steaming milk does not affect lactose. However, over-steaming milk leads to a Maillard reaction. Lactose reacts with protein molecules to form brown and burnt taste.
The primary thing here is to understand how various components of milk react to heat. Ensure you achieve thick, smooth-steamed milk with foam. From there, you are going to make a variety of coffee beverages, including the wet and dry cappuccinos.
Wet and dry cappuccinos
Italians invented cappuccino in the 16th century. It was named after Capuchin Monks, who wore light brown garments with pointed hoods. Back then, milk was mixed with strong coffee to make cappuccino.
Today, cappuccino is made of two shots of espresso. This bitter and robust blend of coffee is mixed with smooth, sweet-steamed foam milk that floats above it. Use two shots of espresso, the barista at the top with an equal amount of steamed milk and an equal amount of foam at the top.
A wet cappuccino comprises more steamed milk and a thin layer of foam. Milk is the canvas for latte art with a preferred thicker layer of foam.
Dry cappuccino uses less steamed milk and more foam. However, the amount of foam added to cappuccino does not affect the taste and enjoyment we get from it. The foam will give the creamy sensation in your mouth. The bursting of the bubbles triggers flavor through the sense of smell. You have a choice to make, enjoy the dry cappuccinos or the wet cappuccinos.
Bone dry vs Super wet
Although ‘wet’ and ‘dry’ are where most people stop with their creation of Cappuccino, others like to push the limits of cappuccino milk ratios.
- Bone Dry— Usually means you’re going to want zero steamed milk; just a big dollop of foam right on top. It’s going to be like a macchiato, but with a little bit more foam. Super Wet — Usually means you want zero foam and all the vaporized milk.
- Super Wet— Typically, you want zero foam, and all the milk that is steamed. This extra-liquid beverage begins to look more like a Cappuccino than a Flat White.