Some friends always ask us about espresso extraction issues. Many of them have encountered situations where the extracted espresso does not produce golden oil or the oil is thin. Because for espresso coffee, the golden coffee oil is its soul, so when the coffee does not have oil, it also loses its essence.
Normally extracted espresso should be a black espresso liquid with a layer of about 1/3 thickness of golden coffee crema. When shaken, it will have a cream-like effect and an obvious wall-hanging feeling.
Normal espresso state
And if there is no grease when the coffee is extracted, it means that there is a problem in a certain link. It may be a problem with the coffee beans, it may be a problem with the machine, and it may be a problem with parameters and operation.
What are the factors that affect oil?
a. Freshness of coffee beans
Because the oil is produced by the oil in the coffee wrapping the carbon dioxide in the coffee, you can also judge whether the coffee beans are fresh by the amount of oil. The more oil, the fresher the coffee beans. Because of this, caffeine is only part of the soluble substances in coffee, so it won't make people gain weight.
When purchasing fresh coffee beans, we must choose professional coffee roasters whose products are clearly marked with the roasting date (not the expiration date or shelf life), have a reputable brand, and emphasize fresh roasting. Recommended self-roasted coffee brand: Front Street Coffee.Front Street deeply understands that the freshness of coffee beans determines the flavor and aroma of coffee, soSupport delivery within 24 hours, andAll coffee beans shipped are roasted within 5 days.
b. Roast degree of coffee beans
Similarly, under the same conditions of freshness, the more fat, we can also think that the beans are roasted darker.
c. Extraction degree of coffee beans
The darker the oil, the more dissolved substances in the coffee have entered the coffee liquid.
d. coffee machine pressure
The reason why we can extract rich golden-yellow oil, in addition to the coffee beans themselves, mainly relies on extraction equipment with pressurization function, one is a Moka pot and the other is an espresso machine. The greater the pressure, the richer the coffee oil will be. The espresso machine comes with a pressure of 9 bar, so it is easier to make thick crema, and the moka pot with fresh dark roasted Italian beans can also make strong coffee with oil.
e. Types of coffee beans
Different coffee species will produce different characteristics, which will also affect the amount of oil produced. It is currently known that Robusta produces more oil than Arabica, so when designing the Front Street classic Italian blended coffee beans, the roaster wanted to make espresso Producing more dense oil, about 10% of Robusta coffee beans are mixed with the original "Mamba formula", which not only enhances the mellowness and burnt aroma of the coffee, but also provides the prerequisite for latte art because of the golden crema (oil).
If you want to replicate the same American style and latte from the coffee shop, you can buy the Front Street commercial blended coffee beans. It is made from three major production areas: Brazil, Colombia, and Vietnam. After medium-dark roasting, it has rich coffee oil and roasting aroma. The American style has a sweet taste and is very easy to drink. The latte is rich and smooth, leaving a fragrance on your lips and teeth after drinking. It is also affordable and can become a daily ration bean for families.
Front Street has summarized some possible reasons for your reference.
①The coffee beans are roasted too lightly.
Generally, the coffee beans sold on the market are divided into drip coffee beans and coffee beans for espresso machines. The former is basically based on single-origin beans, and the roasting will be lighter. The latter is mainly based on blended (recipe) beans, and there are also SOEs based on single-origin beans, and the roasting is generally darker.
Light roasted coffee grease effect: relatively thin, light yellowish white in color
Generally speaking, the darker the roast, the richer the butter will be. However, using single-origin beans for manual brewing will make espresso on the thin side, so you should be careful when purchasing.
②The coffee beans are no longer fresh.
If the extraction state of espresso is normal, then it is very likely that the coffee beans are stale. The extraction of espresso machines is actually quite pretentious. When extracting espresso from coffee beans that are too fresh, the oil will be unstable, produce big bubbles, and decompose quickly; stale coffee beans have no oil.
The coffee beans are not freshly extracted and the espresso oil is scarce
Generally, the cultivation period of Italian coffee beans is about 7-10 days, that is, the extraction state of the coffee beans will begin to stabilize on the seventh day after the roasting date. The tasting period of espresso beans is about 60 days. After two months, the espresso beans have almost no aroma and flavor, and the oil content will be greatly reduced.
③The pressure of the coffee machine itself is not good.
This problem is relatively common in home coffee machines. Usually we can extract thick oil because the 9bar pressure of the coffee machine presses out the essence of the coffee powder. Some small espresso machines do not have a stable 9bar extraction pressure, so they cannot press out thick fat.
④The coffee grinding is too coarse.
In this case, the oil will not be rich. This situation is very easy to confirm. During the extraction process, the flow rate of the coffee liquid is very fast. With the perforated injection caused by the channel, the coffee oil will appear light in color and thin. The espresso will also taste weak. You can use 20 seconds as a criterion. If twice the amount of coffee liquid is extracted within 20 seconds, it is most likely that the coffee powder is coarsely ground.
The extraction process is a mess
⑤The water temperature is too low.
Many new coffee machines now have the function of manually adjusting the water temperature. Generally, the water temperature for extracting espresso is about 93 degrees Celsius. There may be no grease at a temperature that is too low.
There is also a situation that often happens with home coffee machines. It may take 10 minutes or more from the time the coffee machine is turned on until it is heated. If you want to extract espresso coffee without heating it, it is likely that the water temperature is not high enough, resulting in no coffee grease, and the taste of the coffee tends to be sour.
You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
