How Do You Drink a Dirty Coffee and What Milk Ratio Works?

A Dirty is served only iced, built in a chilled glass with cold fresh milk first and hot espresso poured on top, and no ice. Sip it without stirring to move from warm, rich coffee into cool, milky sweetness as the layers blend. A Flat White, by contrast, is hot only and highlights the coffee itself.

The Flat White stays between 160 and 200 milliliters, uses a double ristretto base, and carries about 5 millimeters of milk foam, less milk than a latte. For a Dirty coffee milk ratio, the milk fills most of the glass and the espresso sits on top, so the volume of cold milk and the temperature gap between the two layers drive the effect.

Dirty and Flat White are two popular off-menu espresso drinks at Front Street Coffee. Although both are combinations of espresso and milk, they take completely different routes in temperature, milk volume, milk foam thickness, cup type, and even drinking method. Starting from their respective characteristics and differences, this article will break down the causes of Dirty's layered effect and key production points, explain the recipe approach for Flat White, and also touch on how to choose cost-effective espresso beans. Friends who enjoy milk coffee might as well follow Front Street's steps and try making them at home.

For more specialty coffee knowledge, welcome to follow our WeChat official account: Front Street Coffee (FrontStreet Coffee).

Hidden in Front Street Coffee's espresso menu are two rather understated choices: one is Flat White, and the other is Dirty. What exactly is the difference between them? Today Front Street will explain in detail.

Dirty Coffee

The cup for making Dirty needs to be chilled in the refrigerator in advance. After taking it out, first pour in refrigerated fresh milk, then top it with espresso. Visually, the coffee liquid seems to leave traces on the white milk; when you take a sip, hot and cold intertwine, creating a rather unique layered sensation.

Flat White

Traditional Flat White is usually controlled between 160ml and 200ml, with a base made by combining Double Ristretto and milk. The milk foam thickness of Flat White is about 5mm, and drinking it leans more toward highlighting the flavor of the coffee itself.

What is the difference between the two?

Standard Dirty can only be made iced. Hot espresso enters cold milk to form layers. When drinking, you first experience a warm, rich coffee flavor, then transition to cool, milky sweetness. One drink can deliver several different experiences.

Traditional Flat White, on the other hand, is only made hot. It is a milk coffee with a thin layer of milk foam. Because the milk volume is less than a latte, what hits the palate is a solid coffee flavor, and the mouthfeel is also more delicate.

How do you make a successful Dirty?

Dirty Coffee generally uses a glass cup that can clearly show the liquid, and no ice is added. The key is that the espresso flows into the white milk, slowly penetrating and gradually blending to form a beautiful layered effect. As time passes, the white milk is little by little "invaded" by the espresso. Looking through the glass, the drink takes on that dirty appearance.

1. Chill the cup

First prepare a nice-looking glass cup and put it in the refrigerator to chill. The cup temperature must be low enough so it will not raise the temperature of the iced milk.

2. Milk

For milk, it is recommended to use whole fresh milk. This ensures full flavor and also makes the milk thick enough (enough to "hold up" the espresso). Second, the milk temperature should be low. Because no ice is added, the concentration will not be diluted, and the low temperature can only be maintained by the milk itself. If you want a richer milk flavor, you can also use Icebock as a substitute.

3. Espresso

Dirty has fairly high requirements for espresso. The basic requirements are a strong flavor and rich crema, so that the overall espresso is light enough and will not easily sink. The demonstration below uses Front Street's classic espresso blend, composed of dark-roasted Front Street Mandheling, Front Street Brazil, and Front Street Robusta coffee. The combination of the three provides the espresso with ample crema and a rich, mellow aroma.

4. Technique

Front Street's ratio for making Dirty is 150g milk to 40g espresso. First take out the chilled glass cup and confirm there are no water droplets on the wall, then pour in the iced milk. Next, lock on the tamped portafilter and place the glass cup with iced milk under the spout (if using a bottomless portafilter, just place it directly under the outlet).

The spout should not be too high above the liquid surface, otherwise the penetrating force from the coffee's own gravity will be stronger and it will easily "blend in." It is recommended to keep it at about 1cm. Qualified espresso has an even flow rate and will slowly flow onto the surface of the milk and float there, then gradually sink, forming that dirty look.

Tasting

There is no need to stir Dirty, and it should be drunk as soon as possible, while the upper layer of hot espresso has not yet been cooled by the ice and the lower layer of milk has not yet been "contaminated." From the rich chocolate-flavored hot coffee to the milky, icy, lighter coffee, that transformation is truly wonderful.

How should Flat White be made?

Below is today's Flat White recipe from Front Street Coffee.

The coffee beans used are Front Street's specialty blend, medium-dark roasted, composed of semi-washed Brazil Cerrado coffee and washed Colombia coffee. The dark chocolate and caramel aromas are very rich, and when paired with milk they often present nutty cookie and cream flavors.

To make the base of Flat White, Front Street uses espresso and extracts 30g of espresso liquid from 20g of coffee powder in 20-23 seconds.

Next, steam the milk. For the cup, Front Street uses a 220ml crystal glass. The milk foam should be as little and as thin as possible. Pour the steamed milk into the espresso, integrate until eight-tenths full, then gently push out a pattern. Because Flat White's milk foam is rather thin, patterns can easily become distorted, so it is recommended to make a relatively simple heart pattern, a single dot pattern, or simply skip latte art altogether.

Tasting: The chocolate cream flavor is very rich, and the mouthfeel is full and smooth.

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