WHAT IS FROTH?
What is Froth?
Froth, or foam or microfoam, is milk that has been heated up with high pressured steam. It is that light (soap bubble) foam that sits atop your traditional cappuccinos, or that creamy silky smooth white layer that gives you your latte art in most specialty coffee joints.
How to Froth Milk?
Espresso machines are the ideal way to froth milk. The espresso machine’s steam wand is placed into the pitcher of milk and the steam wand is turned on. A steady stream of steam shoots into the pitcher through the steam tip. The steam tip has either 2 holes, 3 holes, or 4 holes. As the milk heats up, the barista pulls down the pitcher so that the holes meet the surface level of the milk in the pitcher. This creates a paper tearing like sound – this is the milk frothing. In properly foamed milk, a tornado like whirlwind swirl is created in the pitcher. When the desired temperature and amount of foam/froth is reached, the steam wand is turned off.
Steam wands may be flexible or fixed, and the temperature of the steam may be adjusted to suit different frothing styles.
Why Froth Milk?
Besides getting that pretty microfoam needed for latte art, frothed milk is sweeter than cold milk, which, when added to espressos, balances out the punch or bite of the espresso, making it easier and more palatable well, for most people who do not enjoy espressos.
Why is frothed milk sweeter?
Milk is made up of the following composition (Source: Milk Facts)
Let’s talk about the main components of milk that make frothed milk sweeter.
Lactose, a combination of glucose and galactose, is the ‘sugary/sweet’ part of milk. When cold, this combination is just okay sweet, like you would taste in cold milk. As steam is introduced to the milk, the heat breaks down these carbohydrates into simpler sugars, which are then sweeter by themselves. But be careful here, because, if the heat is too high, the sugars break down too much, and the sweetness will disappear. This why specialty coffee places do not enjoy serving ‘extra hot’ lattes as it takes away the overall sweetness of the coffee.
Fat, is what makes lattes so enjoyable. Fat gives milk its buttery creaminess and smooth texture. This is also what makes for a good microfoam latte art pour. When you ask for Skinny lattes, you are asking for skim milk, which is milk that has less fat content than whole milk. The lesser fat makes a drier and lighter foam, which is does not integrate with the non-frothed part of the milk in the pitcher. This in return makes it hard to pour a good latte art as the drier foam does not ‘flow’ with the rest of the milk during the pour. The lighter skim milk is also less creamy in a latte which may take away from the overall balance of the latte.
The protein in milk is made up of a hydrophillic part (attracted to water), and a hydrophobic part (repelled by water). As the steam heats up the milk and creates bubbles, the proteins are broken up, and the hydrophobic part moves to the bubbles, while the hydrophillic part moves towards the water component of the milk. It is this movement and arrangment that holds the foam together. If the heat is too high, the structure is messed up, which results in less silky foam.
Milk, when properly microfoamed, has a silky sheen on its surface and is easy to pour.
Written by Tiffany, Founder & Filter Addict at The Tiny Roaster
Tiffany set up The Tiny Roaster with co-founder Alex in 2013, roasting and brewing only filter coffees at their 1st space at Clementi West Street 1.
Choice coffees: Filters! anything from Kenya, and cold brews.
When she's not drinking coffees, Tiffany enjoys her whiskeys and a good charcuterie board.