Why does iced American coffee look cloudy? Is black coffee turbid because of "impurities"?

People who often drink black coffee know that under normal circumstances, a cup of iced American style will appear thick and dark black, but it will be slightly transparent and clear in the sun. However, some iced American style is visibly turbid and has a hazy texture. The soup color is also particularly dark. So is this normal? Does it have anything to do with the quality of coffee?

Before answering the question, let's first take a look at what the "turbid matter" is in Ice American style. Here, Front Street uses two espresso beans with different degrees of roasting to extract and concentrate, one is the medium roasted Front Street. SOE, one is the front street with medium and deep baking. Match them together classics, make them into ice American style, and then observe their visual state.

Front Street. Huakui SOE Ice American Extraction Parameters: 20 g coffee powder, 33 seconds, 38 g coffee liquor, add 90 g ice cubes and 150 ml room temperature drinking water;

Front Street. Classic ice American extraction parameters: 20 g coffee powder, 28 seconds, 40 g coffee liquor, add 90 g ice cubes and 150 ml room temperature drinking water;

It is not difficult to see from the pictures that although both cups of coffee contain grease, the front street. The color of Huakui SOE Ice American style is lighter and the foam is less, making the coffee liquor look very low in transparency and many "impurities" can be seen to the naked eye. Although the classic ice American combination has a dark appearance, although it is not transparent, it can also present a dark visual effect under normal light.

Tastically speaking, Front Street. The Huakui SOE Ice American entrance has bright citrus acid and pineapple aromas, accompanied by a black tea feeling and a sweet chocolate sweetness, with a clear and clean charm; Qianjie. The classic ice American pairing tastes strong aroma of cream, roasted hazelnut and maple syrup. The flavor is sweet and solid, and it belongs to the body mellow type.

Subsequently, Qianjie used filter paper to filter two cups of ice American style. In the end, both cups of coffee left a thin layer of coffee powder on the filter paper, but the SOE of Huakui was significantly more. In other words, the "turbidity" we see here is actually caused by the extremely fine powder brought by espresso coffee.

Compared with other extraction methods, the bottom of the metal filter powder bowl we use when making espresso is composed of many small holes. These holes are not only the key to bringing delicious taste, but also one of the "culprits" in reducing the transparency of coffee.

We also know that the espresso machine uses 9 atmospheres for extraction. In addition to some components that are easily soluble in water, it will also forcibly squeeze out some proteins, lipids, etc. that are not soluble in water under high pressure. Particle matter, and some very fine powder also pass through the metal filter into the coffee liquor, causing the American style to become not clear enough.

It is not difficult to see from the two cups of iced American style above that the medium baked SOE is more "turbid" than the medium and deep baked classic American style. The lighter the roasting degree of coffee beans, the shorter the heating time. In order to coordinate the extraction rate, we tend to use a finer degree of grinding, which is accompanied by an increase in the amount of extremely fine powder, so these tiny particles are very likely to be extracted. May pass through the holes in the powder bowl and flow into the coffee, causing turbidity.

Moreover, the overall color of the American style made from light roasted beans is light, mainly reddish brown, which is easier to detect than dark, deep-roasted coffee. When the very fine powder particles are suspended in the coffee liquor, we will see it more clearly., subconsciously thought it was "very turbid."

Drinking coffee pursues freshness, but too fresh coffee beans are also one of the reasons for the turbid ice American style. Because the coffee beans at this time are full of active carbon dioxide, the concentrate contains a large number of small bubbles that are not delicate, which will suspend in the coffee liquor, thus affecting the final visual effect.

In addition to roasting degree and freshness, ice American turbidity is also related to the cold and hot coffee. Due to the different ease of dissolution of various ingredients in coffee beans in water, some ingredients can be easily dissolved whether cold or hot; the solubility of some ingredients will increase with the increase of water temperature, and ice water will cause such substances. The decrease in solubility makes the coffee more likely to cause turbid. Because of this, iced coffee has a higher probability of becoming turbid than hot coffee.

When we put aside the appearance of coffee, these fine particles actually have multiple advantages to a certain extent. They not only add flavor and richness to espresso coffee, but also extend the aroma in the mouth. The "tiger spot", which is deeply fascinated by coffee lovers, is also due to the extremely fine powder. For example, Dangna Front Street. When the flower kui is made into SOE American style and hand-washed respectively, the former has a bit more mellow and nutty aroma than the latter, and its body is thicker.

FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou China, selling freshly roasted beans from its own farm in Yunnan as well as dozens of carefully selected single-origin beans from around the world for both pour-over and espresso. The products deliver consistently excellent quality and great value, with shipping within 24 hours. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers, and the beans are now available online at the Tmall 。

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473