Is a dirty latte vs iced latte difference about the milk or the pour?

A dirty latte and an iced latte differ in milk and layering, not in espresso amount. Ice Bock milk is made by freeze-concentrating milk, a technique borrowed from German Eisbock beer, where water freezes at 0°C before fat and protein. The result is a denser, sweeter milk that sits on top of the espresso instead of mixing through.

The dirty coffee milk ratio matters because the concentrated milk is heavier than regular milk, so a slow pour over ice keeps the layers visible. Regular iced lattes use plain cold milk and blend evenly. Shops that use Ice Bock milk often treat it as a signature drink, and the same carton can be concentrated at home with a freezer and a strainer.

Ice Bock milk coffee has sparked a craze in the coffee world in recent years, with many shops featuring it as a signature product, and the chilled refined milk launched by Biru has further fueled this trend. But even before that, some coffee shops were already making drinks with homemade Ice Bock milk. So what exactly is Ice Bock? How does it differ in flavor from a regular latte? This article will start with the origin and principles of Ice Bock, teach you step by step how to make Ice Bock milk at home, and share Front Street Coffee's review of Ice Bock milk's flavor characteristics, as well as its excellent performance when paired with espresso to make a Dirty.

Recently, whether large chains or independent shops, everyone has been launching Ice Bock milk coffee. A major driving force behind this is the [Ice Bock] chilled refined milk launched by the Biru brand. However, even before this product came out, quite a few cafes were already using Ice Bock milk coffee as a signature to attract customers. So how exactly do these shops make their Ice Bock milk?

What exactly is Ice Bock?

The name Ice Bock is a transliteration of the German word Eisbock, which originally referred to a beer freeze-concentration process, namely the traditional German ice beer. Its core logic is that different substances have different freezing points, so different components can be separated by controlling temperature. Apply the same idea to milk, and you get Ice Bock milk.

Take milk, for example: the freezing point of its water content is 0°C, while the freezing points of other components such as protein and fat are lower than that of water. If you place milk in an environment of -20°C, the water will freeze first, and only after the temperature continues to drop to the freezing points of the other components will the entire carton of milk freeze solid. Conversely, during the melting stage, the other substances will also melt out earlier than the ice. By exploiting the differences in freezing points among milk's components, you can achieve separation of water and milk fat, ultimately obtaining a more concentrated milk—this is the origin of Ice Bock milk.

How to easily make Ice Bock milk at home?

FrontStreet Coffee currently does not offer Ice Bock coffee in its stores, but here we can demonstrate a home method for making Ice Bock. The materials needed are very simple: just a carton of milk and a container to catch the Ice Bock.

① First, put the entire carton of milk in the refrigerator's chilled compartment. Front Street chose a 946ml carton of Vitasoy fresh milk and left it in the refrigerator for 12 hours to let the milk freeze completely into ice. The frozen milk carton will bulge noticeably, and when you squeeze it hard with your hand it feels very solid, which is how you tell whether it has frozen completely.

② Take the frozen milk out of the refrigerator, cut a small opening just like you normally would when opening a milk carton, then turn the carton upside down over a container, and seal the milk carton together with the glass container using clean plastic wrap or a fresh-keeping bag, securing it with tape. This has two benefits: first, it makes the structure more stable and prevents it from collapsing; second, it isolates it from outside contamination, especially moisture in the air—after sealing with plastic wrap, water vapor will not condense into droplets and drip into the container.

③ Leave it at room temperature to melt naturally. The milk will drip into the container drop by drop, and usually you can collect 40% to 60% of the original volume as liquid. If you prefer a rich milk-candy aroma, you can take only 40%; for a normal taste, choose 50%; and if you don't want to waste too much milk, you can go to 60%. After a long 4 hours, 450ml of Ice Bock milk was finally obtained. In other words, one 946ml carton of fresh milk ultimately produced 450ml of Ice Bock.

What does Ice Bock milk taste like?

The milk obtained through the Ice Bock process is very pure, with a more pronounced milky aroma when smelled and a thicker texture. After actually tasting it, Front Street found that its sweetness is very high and its mouthfeel is very rich. After drinking Ice Bock milk and then drinking ordinary fresh milk, the latter will feel as bland as water. But precisely because the concentration is so high, drinking too much Ice Bock milk at once can make people feel it is cloyingly sweet and a bit greasy.

Therefore, combining Ice Bock milk with espresso makes the most ideal pairing, such as the very popular Ice Bock Dirty in coffee shops.

The flavor of Dirty mainly depends on the espresso beans used. Front Street stores use their own roasted "Sunflower Warm Sun Blend," made from 70% Honduras Sherry coffee beans and 30% Yirgacheffe sun-dried Red Cherry coffee beans. The whiskey aroma, vanilla, and creamy notes brought by the Sherry, combined with the tropical fruit character and fermented feel of the Red Cherry, give the whole cup a rich aromatic layering and a soft mouthfeel. The first sip of Ice Bock Dirty delivers a strong coffee aroma, presenting flavors of whiskey, vanilla, and berries. From the second sip onward, as the iced milk gradually blends in, you can feel a cocoa and creamy texture. After finishing, the sweet aroma of espresso and milk remains in the mouth, with very distinct layering.

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