What Temperature is Best for Coffee Milk Foam: 30°C, 60°C, or 90°C? Different Temperature Performance Analysis

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The Ideal Temperature for Milk Foam in Milk Coffee

We often say that the ideal temperature for frothing milk foam in milk coffee is around 50-70°C. Why is this? Today, let's explore this question together.

I prepared four cups of milk foam at different temperatures to observe how the foam dissipates over time. The milk frothing temperatures were: 90°C, 60°C, 30°C, and 12°C.

The Milk Frothing Process

(The image above shows the beginning of foam dissipation)

Results at Different Temperatures

90°C: At temperatures above 70°C, the milk foam expands rapidly even without intentional frothing. Due to the high temperature and continuous rolling, by the time it reached 90°C, the milk had already overflowed from the pitcher (as shown in the image above), stopping at 94°C. Significant foam dissipation appeared at around 1 minute 30 seconds.

60°C: This is the temperature we commonly use. Following standard frothing procedures, I stopped when it felt too hot to touch, at 63°C. Significant foam dissipation appeared at around 10 minutes 50 seconds.

30°C: Using regular frothing techniques, the milk felt warm to the touch, stopping at 33°C. Significant foam dissipation appeared at around 4 minutes 20 seconds.

12°C: For this, we used milk directly from the refrigerator, using a manual frother. The milk poured into the frother was 8°C, and after frothing, it reached 12°C. Significant foam dissipation appeared at around 5 minutes 15 seconds.

After observing the milk foam, I selected three temperatures of milk foam to add to coffee for comparison.

I used FrontStreet Coffee's premium espresso beans for testing (roast level: medium-dark roast; coffee beans: 100% Arabica, Colombia 4: Brazil 6 blend ratio).

Espresso: 40 grams, extraction time: 25 seconds.

80°C: The foam was quite coarse, with significant dissipation visible on the cup walls. The foam pattern spread slightly. Dissipation time: around 2 minutes 30 seconds.

60°C: After dissolving to a certain extent, the foam remained stable and dense, with visible tiny bubbles. The foam pattern spread outward, similar to the 80°C case. Dissipation time: around 6 minutes 15 seconds.

40°C: After dissolving to a certain extent, the foam remained stable but was slightly coarser than the 60°C foam. The foam pattern spread more noticeably. Dissipation time: around 3 minutes 45 seconds.

Conclusion

From the above experiments, we can conclude that milk foam in the 50-70°C range has the best durability both in pure milk and when added to coffee. There are two reasons for this: First, there is sufficient time for the foam and milk liquid to mix and become smooth after frothing. Second, it falls within the period when milk begins to denature but hasn't reached irreversible denaturation, providing higher stability.

When milk foam is frothed to around 80-90°C, irreversible denaturation occurs in milk. Milk contains two types of proteins: whey protein and casein. Whey protein begins to denature above 60°C. Therefore, when we froth to around 90°C, the protein elasticity is insufficient, causing the foam to dissipate more quickly.

When milk foam is frothed to around 30-40°C, the rapid dissipation is caused by insufficient mixing time between the foam and milk liquid after frothing.

The reason cold milk foam dissipates quickly is that we used a manual frother. The degree of mixing cannot compare to the high-speed mixing of a steam wand. The fusion is not high, and during the transition from low temperature to room temperature, the milk foam undergoes a heating process. Under the pressure of external heat, the internal gas expands, causing more noticeable foam bursting.

Therefore, the ideal temperature for a cup of milk coffee is within the 50-70°C range, which is also suitable for drinking - neither too hot for the mouth nor too cold.

Important Notice :

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