Milk composition: proteins, fats, lactose

Proteins

• Types: Casein (≈80%) and whey proteins (≈20%).
• Role in Steaming:
• Caseins form micelles that stabilize milk foam.
• Whey proteins denature with heat, helping to bind air and water.
• Impact on Latte Art: Stable foam with fine microbubbles creates a smooth canvas.

Fats

• Content: Typically 3–4% in whole milk.
• Role in Mouthfeel: Provides creaminess, body, and richness.
• Impact on Foam:
• Higher fat → richer taste but less stable foam.
• Lower fat → drier, more stable foam but less creaminess.
• Balance: Whole milk offers the best compromise for both latte art and taste.

Lactose

• Definition: Milk sugar (≈4–5%).
• Role in Flavor: Adds natural sweetness, especially as milk is steamed (perceived sweetness increases).
• Caramelization: Lactose does not caramelize like sucrose, but heat enhances perception of sweetness through protein-lactose interactions.

Interactions During Steaming

• Proteins stabilize foam structure.
• Fats influence foam richness and mouthfeel.
• Lactose contributes background sweetness that complements espresso bitterness.

Summary

Milk’s composition determines its performance in coffee: proteins stabilize foam, fats provide body, and lactose gives sweetness. Understanding these components helps baristas steam milk to achieve the right balance of texture, flavor, and latte art potential.

• Tags:
• Latte Art
• Milk Foam
• Perceived Sweetness
• Helps Baristas