Latte Art Foam Steaming Tutorial: How to Achieve Dense, Smooth, and Long-lasting Milk Foam

(os: Today's latte art looks great!) A couple of minutes later... The foam collapses! "Craters" appear one by one, and the latte art doesn't look good anymore... Why!!

(The emotional journey of a latte art practitioner)

Looking at foam that resembles the surface of the moon is truly frustrating. Don't worry! FrontStreet Coffee is here to analyze the reasons behind this collapse phenomenon~ (Quick, grab your notebook and take notes 📝)

The Composition of Milk Foam

What affects foam stability is the casein micelles in milk protein and whey protein. The presence of casein micelles creates tension on the milk surface. When steam impacts the milk surface, numerous bubbles of varying sizes form. Then, by adjusting the steam wand position to create a vortex in the milk, larger bubbles are "chopped up," resulting in fine foam with a smooth texture.

(I am image two)

Causes of Rapid Foam Collapse

Milk Frothing

1. Use chilled fresh milk: Chilled fresh milk contains abundant protein and milk fat. Protein is key to foam formation, while milk fat is one of the main factors that stabilize foam. This also explains why using skim milk to make lattes causes foam to break down more quickly.

2. Release steam before each frothing session: When the steam wand is not in use, moisture condenses in the steam holes. If this moisture isn't released before frothing, it will affect the difficulty of milk frothing. If the foam isn't frothed finely, it will naturally decompose faster.

3. Milk frothing temperature: Generally, the recommended frothing temperature for milk is between 55-65°C, not exceeding 70°C at most. If the frothing temperature is too high, it will cause protein decomposition, reducing foam stability and accelerating foam breakdown.

4. Excessive tapping of the milk pitcher after frothing: Many people have the habit of tapping the milk pitcher after frothing is complete, with the goal of eliminating large bubbles on the surface. However, continuous tapping will accelerate the dissipation of fine foam, making it prone to collapse after blending with coffee. Therefore, FrontStreet Coffee does not recommend continuous pitcher tapping. Generally, tapping 2-3 times after frothing is sufficient. If there are still many large bubbles after 2-3 taps, we recommend re-frothing the milk, as too many large bubbles not only look unattractive in latte art but will also quickly create large "craters" on the foam surface after blending.

Espresso Coffee

1. Freshness of coffee beans: Overly fresh coffee beans contain large amounts of carbon dioxide. During extraction at 9Bar pressure in a sealed state, carbon dioxide and water exist in a supersaturated state. At the same time, coffee oils are emulsified, then encapsulate the carbon dioxide and extract it together with the coffee liquid. After extraction, the carbon dioxide in the oils will continuously return to the air. When blended with milk, the release of carbon dioxide will accelerate foam collapse.

2. Espresso extraction: If extraction time is too short, the espresso crema will be too thin, causing scattering when milk and coffee blend; if extraction time is too long, the espresso crema will be too thick, making it difficult for milk and coffee to blend evenly. Both situations will result in uneven blending of milk and coffee, which is also one of the reasons why foam easily collapses.

Blending

As mentioned above, the degree of blending between coffee and milk also affects the decomposition speed of foam on the surface of latte coffee. Generally, the higher the degree of blending, the more stable the foam will be, and the decomposition rate will slow down. If blending is uneven and the coffee surface is rough, the foam will become unstable and decompose faster. The best blending for latte coffee is when the liquid surface color is uniform and the surface is fine and smooth. (As shown in image two of this article)

(Uneven blending of milk and coffee)

To achieve uniform blending of milk and coffee, besides fine foam of appropriate thickness, the size of the milk flow during blending and the speed of circular motion are also important factors.

Generally, the milk flow size during blending will be slightly finer than during the latte art design phase, with the goal of allowing full integration of foam and coffee without damaging the cleanliness and color of the crema. Too rapid circular pouring will easily create large bubbles, while too slow circular pouring will make it difficult for milk and coffee to blend fully.

-Great! Another useful piece of knowledge has been added-

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473