Can Dirty Coffee Be Made Hot? A Visual Guide to Hot Dirty Coffee Recipe

Those familiar with FrontStreet Coffee know that besides the beverages listed on the blackboard at our café, there are actually quite a few hidden menu items, such as Flat White, Espresso, Dirty, and more. With Guangzhou's temperature fluctuations resembling an EKG reading, a regular customer at FrontStreet Coffee hesitated for quite some time before placing their order, finally posing the soul-searching question: "I don't want something cold, but I'd like to try a Dirty. Why can't you make it hot?"

Dirty: I'm Meant to Be Cold

In most people's minds, Dirty coffee might have gained popularity around 2018-2019 as part of the "dirty culture" trend, leading to the misconception that Dirty was a specialty coffee created during that period.

However, Dirty was actually created by Mr. Katsuyuki Tanaka from Japan. In 2009, he opened a café called "Bear Pond Espresso" in Kitashizuku, Tokyo, and Dirty was already a specialty product he made when he first opened, named "B.P Dirty" on the menu.

The core of this Dirty lies in Tanaka's use of a rather special espresso— "Angle Stain" (Angel's Stain). He used deeply roasted coffee beans, extracted with a large dose of ground coffee in a short time to create an ultra-concentrated, low-extraction-rate espresso liquid. He specifically used a bottomless portafilter, judging the extraction status by visual observation (the color of the extracted espresso liquid changes from dark to light), and finally removing the coffee cup at the right moment. The uninterrupted stream of coffee liquid would leave tear-like traces on the cup wall, thus earning the name "Angle Stain."

Using this espresso extraction method combined with iced milk to make Dirty not only creates a lasting and obvious layering effect but also provides a rich tasting experience—from bitter to sweet, from hot to cold. Therefore, Dirty has been served cold since its invention, and due to its completely different tasting experience compared to other espresso coffees, it has transformed from a "trendy" beverage into a staple on café menus.

Attempting to Make Dirty Hot?

The main reason for Dirty's layering is the density difference between iced milk and hot espresso, causing the espresso liquid to sink and mix slowly. If we want to make a hot Dirty, we would need to heat the originally large proportion of iced milk, while the espresso would need to be iced instead—swapping their temperatures to maintain the density difference and achieve the layered effect of coffee and milk.

It sounds simple enough—heating iced milk takes just minutes, but making iced espresso is troublesome. If we put espresso directly into the freezer for rapid cooling, by the time it cools down, the crema and most aromatic compounds will have dissipated; if we add ice cubes, it will dilute the coffee concentration, making it impossible to achieve the layering effect, and Dirty would become an ordinary latte.

Therefore, FrontStreet Coffee thought of the special ice spheres often seen in competitions in recent years. These pre-cooled ice spheres can rapidly cool the espresso liquid, preserving more flavor compounds. Without further ado, let's conduct the experiment immediately.

Preparation: 150ml of milk; espresso ready for extraction; bottomless portafilter; two pre-cooled special ice spheres; one 200ml glass. (This experiment uses Warm Sun blend coffee beans, with extraction parameters of 19.8g coffee grounds, 29s extraction time, yielding 38g of coffee liquid)

Step 1: Heat the milk to approximately 56°C (just slightly hot to touch)

Step 2: Pour the milk into the glass, ready to receive the espresso

Step 3: Aim the ice spheres at the bottomless portafilter and begin extracting the espresso

Extraction complete, enjoy immediately!

Tasting Notes:

After rapid cooling, the Yirgacheffe acidity in the Warm Sun blend becomes particularly prominent. The first sip reveals almost no milk taste, with distinct textural layers between iced coffee and hot milk; by the second sip, the temperatures of coffee and milk tend to align, with rich espresso bitterness; by the third sip, the entire Dirty has become warm coffee-flavored milk.

When using the same Warm Sun blend coffee, the hot Dirty tastes somewhat inferior to the regular iced Dirty, and the preparation method is complex and demanding (the special ice spheres need to be refrozen after single use). If you want to use hot Dirty to showcase the bean's flavor characteristics, additional adjustments and pairings are needed. In situations with small output volume, it seems somewhat not worth the effort. This is why Dirty is always served cold, and why you won't find hot Dirty for sale in café offerings.

- END -

FrontStreet Coffee
No. 10, Bao'an Qianjie, Yandun Road, Dongshankou, Yuexiu District, Guangzhou, Guangdong Province

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473