Milk Foam Thickness and Espresso Base: What Separates a Flat White from a Latte

A latte and a flat white can look identical when served in opaque cups. Both use espresso, milk, and milk foam. The difference comes down to foam thickness, cup size, and the espresso base. A latte typically has about 1cm of milk foam in a larger cup, often with a standard espresso shot. A flat white has less than 0.5cm of foam in a smaller cup, and many shops use a ristretto shot instead.

Foam thickness changes the drinking experience. A latte's thicker foam supports latte art and adds a creamy mouthfeel. A flat white's thinner foam pours with high fluidity, making detailed patterns difficult, so many cafes skip latte art. Yet that thin layer enhances smoothness and lets the espresso's flavors come through more directly. These small details explain why the two drinks taste distinctly different.

Flat White and Latte are often hard to tell apart visually, especially when served in opaque cups. Both are made from espresso, milk, and milk foam, yet the experience upon tasting is entirely different. The root of the difference lies in the foam thickness, cup size, and the choice of espresso base. A latte has about 1cm of milk foam and a larger cup volume, typically paired with a traditional espresso; a flat white has less than 0.5cm of milk foam and a smaller cup volume, and many coffee shops switch to a Ristretto shot instead. This article starts from Front Street's own preparation parameters, combined with the tasting performance of the Black Cocoa Base Blend, and breaks down the flavor logic and preparation details of these two milk coffees one by one.

From the appearance alone, lattes and flat whites are indeed easily mistaken for the same type of drink, especially when served in cups made of non-transparent material, where the two are almost impossible to distinguish by eye. The reason is not complicated—they use exactly the same ingredients, namely espresso, milk, and milk foam, which is why their finished appearance is so similar.

However, as soon as you actually take a sip, you will find that these two coffees differ noticeably in flavor and mouthfeel. What creates this difference is precisely a few easily overlooked details, such as the thickness of the milk foam.

I. Thickness of the Milk Foam

Milk foam is, in the end, the layer of foam formed after steaming milk. If you pour a latte and a flat white into separate transparent glass cups, the most intuitive difference becomes apparent—the thickness of their milk foam is not on the same level. And the foam thickness in turn affects multiple variables, including the difficulty of pouring latte art and the texture of the coffee on the palate. A latte's milk foam is around 1cm, noticeably thicker than that of a flat white.

Foam of this thickness is very suitable for pouring latte art, because it has enough thickness while retaining proper fluidity, allowing smooth lines to be drawn when you swirl the pitcher, helping you create the desired pattern. At the same time, this kind of foam also adds a richer mouthfeel and a dense, creamy touch to the coffee.

By contrast, a flat white's milk foam is much thinner, not even reaching 0.5cm. Because its fluidity is on the high side, pouring delicate patterns on this kind of foam is not easy, so many coffee shops simply choose to serve flat whites without latte art. But thin foam also brings a notable advantage—it enhances the coffee's smoothness, giving it a velvety, silky texture when drunk.

II. Cup Size

The difference in cup size is also worth noting. A flat white is generally served in a slightly smaller cup than a latte. Although Front Street's storefront does not serve coffee to the public, when Front Street makes flat whites and lattes on its own, it deliberately uses different amounts of milk, which creates a difference in the final cup volume. A latte, because more milk is poured in, naturally has a larger volume; a flat white is relatively smaller.

This difference in cup size comes about because a latte needs a large amount of milk to neutralize the coffee's bitterness, making the overall flavor more balanced and gentle so it doesn't taste too bitter; whereas a flat white seeks to highlight the taste of the coffee itself, so the amount of milk is reduced to avoid the milk flavor overpowering the coffee's flavor.

III. The Coffee Base

Besides the milk, some coffee shops also differentiate the espresso base when making flat whites and lattes. Specifically, lattes use a regular espresso, while flat whites use a short-extraction version of espresso—that is, Ristretto.

The difference between a Ristretto and a regular espresso shows up in two dimensions: extraction yield and concentration. A regular espresso is extracted more completely, has a relatively lower concentration, presents a more balanced flavor, and has a more complete finish;

A Ristretto, because its liquid volume is reduced, has a slightly higher concentration and a correspondingly lower extraction yield. The advantage of this extraction method is that the coffee tastes sweeter on the palate, with a fuller body, less obvious bitterness, and is overall easier to accept.

The above are the three main differences between a flat white and a latte. However, from written descriptions alone, you may still find it hard to truly grasp how the two differ. Next, Front Street will share the specific parameters and tasting impressions of these two coffees, so you can distinguish them more clearly.

The coffee beans Front Street selected this time are the Front Street Black Cocoa Base Blend from its bean list, a blend of coffee beans from Brazil and Yunnan, roasted to a medium-dark level. When making the espresso for a latte, the parameters Front Street uses are: 20g of grounds, a 1:2 coffee-to-liquid ratio, with extraction time controlled at 30 seconds; while the Ristretto used for making a flat white has these parameters: 20g of grounds, a 1:1.5 coffee-to-liquid ratio, also with an extraction time of 30 seconds.

When Front Street makes a latte, the coffee-to-milk ratio used is 1:5 (the ratio of coffee to milk) , that is, 40ml of espresso paired with 200ml of milk. The milk is heated to 65°C and steamed into a thick foam of 0.5cm to 1cm, then latte art is poured, and a latte is complete;

While when making a flat white, the ratio Front Street uses is 1:4 (the ratio of coffee to milk) , that is, 30ml of espresso paired with 120ml of milk. The milk is heated to 55°C and steamed into a thin foam of less than 0.5cm, a simple latte art is poured, and a flat white is ready.

A latte's foam is on the thick side, giving a stronger creamy density on the palate and a richer mouthfeel. In terms of flavor, because milk accounts for a relatively high proportion, the overall presentation is very balanced—the coffee flavor is not overly amplified, nor is it masked by the milk flavor, and you can taste the chocolate, nut, and caramel flavors presented by the Front Street Black Cocoa Base Blend, with a lasting finish and obvious sweet aftertaste;

As Front Street said earlier, a flat white performs completely differently. Because less milk is used, a flat white's coffee flavor is quite intense, and you can clearly sense the flavors of caramel, chocolate, nuts, and cream. However, because it uses a Ristretto, the extraction yield is not complete, so even though the flavor is strong, it doesn't feel bitter—instead, it has higher sweetness. The thinner milk foam gives the coffee a velvety, silky mouthfeel, performing equally well.

Based on the above, I believe everyone can now clearly understand the differences between a flat white and a latte. Distinguishing them is actually not difficult, right~

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