What is the difference between cappuccino and flat white?

Cappuccino and flat white are similar in cup size but taste different for two reasons: the espresso base and the thickness of the milk foam. A cappuccino is built on standard espresso, which extracts sour, sweet, and bitter compounds together, so bitterness carries through the milk. A flat white uses ristretto, a shorter, more concentrated extraction that stops before the bitter tail is pulled, giving a sweeter profile.

During extraction the three flavor groups dissolve at different rates. Sour and sweet compounds arrive early and in the middle of the shot, while bitter compounds release later once the others are largely gone. Ristretto deliberately cuts that tail, keeping the coffee flavor rich without the bitterness. The latte, by contrast, simply holds the highest milk proportion, which is why it reads as the sweetest of the three.

Both are espresso with milk, so why does a cappuccino taste more bitter than a flat white? With similar cup sizes yet completely different flavors, the key lies in two places: the choice of coffee base and the thickness of the milk foam. Starting from the principles of extraction, this article compares the differences in how espresso and ristretto release sourness, sweetness, and bitterness, then uses actual weighing to calculate the effect of milk foam on the milk ratio, fully explaining the essential differences between cappuccino, flat white, and latte, while also clarifying the relationship between flat white and ristretto.

Among these three, the latte has the highest proportion of milk, so it makes sense that it tastes sweeter. But cappuccino and flat white have similar cup sizes, so why is the cappuccino's bitterness more pronounced? This brings us back to the flat white base that Front Street Coffee discussed before.

Divergence in Base Selection

Traditional Italian milk coffees like latte and cappuccino use standard "espresso" as their base, then adjust the taste by adding different amounts of steamed milk; while the base used for flat white is a more concentrated extraction evolved from the espresso method, namely "ristretto."

One prerequisite needs to be understood first: during extraction, the three types of flavor compounds—sour, sweet, and bitter—begin to dissolve together the moment hot water contacts the coffee grounds, but their dissolution rates differ, so the points at which each is released in large amounts also differ. Sour and sweet flavors dissolve more efficiently, and are concentrated in the early and middle stages of espresso extraction. Bitter compounds dissolve more slowly, and only when the sour and sweet substances are almost fully dissolved do they release in large amounts—because by then, hot water can only extract what remains.

It can be said that espresso extraction belongs to the relatively complete category. We need bitterness to support body and suppress the taste of milk, so we must use appropriate parameters to extract sourness, sweetness, and bitterness in suitable amounts; what makes ristretto different is that it pursues a rich coffee flavor without wanting bitterness. Thus it directly abandons the tail end, retaining only the sour and sweet flavor compounds. (For detailed information on ristretto, see the article "Ristretto.")

To put it simply: with the same dose of grounds, extracted respectively as espresso and ristretto, espresso has more liquid weight and therefore more pronounced bitterness; ristretto has less liquid weight and higher concentration, so its bitterness is actually weaker. Therefore, at the same cup size, cappuccino is simply more bitter than flat white.

Thickness of the Milk Foam

Of course, many shops do not set a dedicated extraction parameter for flat white, since the number of cups sold may not even exceed what is consumed while dialing in the machine (such as Front Street Coffee). In this case, flat white directly uses espresso for production. At this point, with the same cup size and same liquid weight, the only thing that can create a difference between cappuccino and flat white is the amount of milk foam.

The most iconic feature of cappuccino and flat white is their respective milk foam. Cappuccino's milk foam is famous for being thick, as fine, dense, and soft as clouds—this is its unique mouthfeel experience; flat white's milk foam is known for being thin, and because it is thin enough, it has strong fluidity, and many people describe its entry as a velvety texture.

Cappuccino's milk foam thickness is about 1–1.5 cm, while flat white's is less than 0.5 cm. Milk foam occupies the milk space in the cup, so at the same cup size, how much milk difference is there between the two?

Taking the 240 ml cup used by Front Street Coffee as an example, the standard for making cappuccino is that the milk foam should overflow the rim, reaching an eleven-tenths full state, while flat white is level with the rim. Let's make one cup of each and weigh how much milk is used when reaching the standard.

After weighing, it was found that the total liquid weight of the cappuccino was 195 ml; subtracting the 40 ml of espresso, the milk weight was 155 ml. The total liquid weight of the flat white was 225 ml; subtracting the 40 ml of espresso, the milk weight was 185 ml, a full 30 ml more than the cappuccino.

It is precisely this extra 30 ml of milk that widens the coffee-to-milk ratio and dilutes the bitterness, so flat white is not as bitter as cappuccino. The reason latte is popular is also because the milk dilutes the bitterness, making the sweetness naturally higher.

Front Street Coffee

No. 10, Bao'an Qian Street, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

The above content is compiled by CoffeeHunters, a coffee news website.