How to Make Dirty Coffee: Ratios, Layering Technique, Glass Selection, Proper Drinking Method, Flavor Profile, and Storage Duration

In recent years, a type of iced milk coffee called Dirty has become increasingly popular. The upper layer of warm, aromatic espresso combines with sweet, delicious iced milk, creating a unique sensation of alternating hot and cold temperatures. Its photogenic appeal adds to its charm, leading many coffee shops to add it to their permanent menus.

What is Dirty Coffee?

Dirty literally means unclean or dirty in English, which is why Dirty coffee is also translated as "dirty coffee." The concept of Dirty originated from the "dirty food" trend that swept through in 2019, but the Dirty coffee of that time wasn't made the way we see it today. Back then, it utilized milk foam or cream to create an overflowing effect, then added cocoa powder, nut fragments, and other toppings to create a "dirty" appearance, similar to the popular dirty croissants of that era.

Today's Dirty coffee emphasizes coffee flavor more, with double shots of dark brown espresso poured over pure white milk. Using gravity, the espresso gradually permeates downward, creating a visual effect of "staining" the milk. It's said that Dirty coffee first originated from a Japanese coffee shop. However, there's no definitive answer about who invented Dirty, nor is there a standardized preparation method, so each coffee shop's version of Dirty might be different.

How to Make Dirty Coffee?

Although the ingredients for making Dirty are simply espresso and milk, FrontStreet Coffee believes that achieving perfect layering and the alternating hot-cold sensation requires certain techniques.

Since Dirty coffee primarily emphasizes preserving the crema from espresso and the visual effect of gradual layering, ice cubes cannot be added during preparation as they would dilute the overall concentration of coffee. Additionally, the milk must have high protein and fat content, and be sufficiently cold, so the rich fats can float on the upper layer. Therefore, FrontStreet Coffee suggests using chilled fresh milk or purified milk (ice blog) when making Dirty.

Since Dirty preparation doesn't involve adding ice cubes, besides pre-chilling the milk itself, the glass should also be kept at an appropriately low temperature. This prevents the milk from losing its temperature to the glass when poured. FrontStreet Coffee needs to remind everyone that when selecting glasses, be sure to check if they are temperature-resistant to prevent accidents like bursting during the freezing process or when pouring hot espresso.

To ensure a rich flavor, Dirty coffee is served in smaller cups than iced lattes. Typically, Dirty coffee is served in 180-220ml cups, while iced lattes come in 280-320ml cups. When FrontStreet Coffee makes Dirty, we first take a pre-chilled glass and pour in 150ml of fresh milk. Then we use 20 grams of coffee grounds to extract 36 grams of espresso liquid, placing the iced milk directly beneath a bottomless portafilter so the espresso lands on the surface. Note that the coffee stream shouldn't be too high, as it could penetrate directly into the milk below, failing to create the "dirty" effect.

How to Drink Dirty Coffee?

The beauty of Dirty coffee lies in its distinct layers, so after preparation, there's no need to stir, nor is a straw necessary. We can simply take large sips to enjoy it. The flavor of Dirty primarily depends on the coffee beans used. FrontStreet Coffee uses our house-roasted "Sunflower Warm Blend," which consists of 70% Honduras Sherry coffee and 30% Yirgacheffe Natural Red Cherry coffee. The whiskey, vanilla, and cream notes from the Sherry combine with the tropical fruit and fermentation characteristics of the Red Cherry, creating rich aromas and a smooth texture in the cup.

The first sip of Dirty coffee delivers rich coffee aromas, presenting whiskey, vanilla, and berry flavors. From the second sip onward, as the iced milk integrates, you can experience a cocoa-like, creamy texture. After finishing, your mouth is left with the sweet fragrance of strong coffee and milk, creating an incredibly rich layering of flavors.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473