What are the extraction standards for espresso? How to adjust espresso grinding ratio parameters

A friend saw FrontStreet Coffee's espresso recipe and went home to try extracting coffee. However, they didn't achieve the desired flavor and returned to FrontStreet Coffee to discuss the issue. Therefore, FrontStreet Coffee would like to take this opportunity to share how to judge espresso during practical operation.

First, any data is only for reference. Simply replicating the data won't necessarily produce the same espresso flavor that FrontStreet Coffee extracts. This involves hard factors like the flavor of coffee beans and the performance of the coffee machine. Therefore, extracting espresso requires learning to operate the machine and understanding the relationships between parameters. The goal is to extract the flavor of coffee beans while avoiding negative flavors.

In daily extraction parameters, FrontStreet Coffee doesn't always stick to 20 grams of coffee grounds to extract 40 grams of coffee liquid within 25-30 seconds. Instead, this parameter is theoretically reasonable, but in reality, the condition of coffee beans changes daily. Therefore, to maintain stable coffee quality, constant fine-tuning of parameters is necessary. These include grind size, dose amount, and liquid output.

"For example, yesterday's parameter was 20 grams of grounds to extract 40 grams of coffee liquid in 28 seconds; today's parameter is 19.7 grams of grounds to extract 40 grams of coffee liquid in 28 seconds (adjusting dose amount); or 20 grams of grounds to extract 35 grams of coffee liquid in 26 seconds (adjusting liquid output); or 19.7 grams of grounds to extract 40 grams of coffee liquid in 30 seconds (adjusting both dose amount and grind size)."

Through such adjustments, the flavor of espresso can be brought back to yesterday's taste (everything is based on flavor and mouthfeel).

In daily practical espresso extraction, we can observe the extraction state and taste the flavor to determine whether the espresso is normal.

Observation

Before extraction, it's important to ensure the coffee machine's temperature and pressure are normal.

Then observe the espresso's output state. Generally, when extracting espresso, counting from when the extraction button is pressed, the first drop of coffee liquid will be pressed out in 4-6 seconds. The coffee liquid appears brownish-black, very viscous, with a slow flow rate. Around the 12-second mark, the coffee liquid's flow rate gradually increases and stabilizes, with a brownish-yellow color and cream-like consistency. Around the 20-second mark, the coffee liquid appears golden yellow with a stable flow rate. As the seconds increase, the coffee liquid's color gradually lightens, and its viscosity gradually thins until the coffee liquid turns white, indicating it's time to end the extraction (usually ending just before it turns white).

If you observe any of the following situations with the coffee liquid, it indicates extraction problems, and you should terminate early and re-extract:

1. Without pre-infusion, it takes more than 10 seconds after pressing the start button for coffee liquid to appear. This is caused by grinding too fine or using too much coffee grounds.

2. Unstable coffee flow rate, sometimes fast and sometimes slow, which might be due to poor distribution and tamping, causing channeling effects.

3. Very fast coffee flow rate, which is caused by grinding too coarse. If the flow rate is normal at first but then becomes very fast, you need to remove the portafilter to observe the coffee puck. If there are only perforations or gaps on the edges of the puck, you just need to pay attention to distribution and tamping. If the puck surface is muddy and uneven, you need to increase the dose amount.

4. After making espresso, you can also observe the quality of the espresso. Generally, espresso crema should be golden yellow, fine, and smooth, with a cream-like texture when shaken. If the crema is rough or clumped, it might be due to coffee being too fresh. If the coffee crema is thin, it could be an issue with the roast degree or the coffee beans being roasted too long ago.

Tasting

Observing the espresso extraction state can only avoid some basic errors. Even if the flow rate is uniform and the ratio and time successfully hit the extraction range, it doesn't guarantee that the espresso will taste good. Therefore, after confirming there are no problems with the extraction process, you need to taste the espresso to determine what adjustments are needed.

The flavor of espresso mainly depends on the coffee beans, so when tasting espresso, you can compare it with the flavor description of the coffee beans. The second is to determine whether the espresso has any deficiencies in flavor or mouthfeel. For example:

1. If the espresso tastes strongly acidic with a short aftertaste, it's possible that too little coffee liquid was extracted, and you can appropriately extend the extraction.

2. If the taste is rich with a burnt bitter flavor, you need to adjust the grind to be coarser.

3. If the taste is weak and the mouthfeel is thin, you need to adjust based on extraction data. If the flow is quite fast and the time is less than 25 seconds, you can appropriately adjust the grind to be finer, reduce the liquid output, or increase the dose amount.

Of course, if you're ultimately going to add milk or water to drink, the best way to taste is after adding milk (water). Just like at FrontStreet Coffee's stores, which mainly serve Americanos and lattes, in the final stage of adjusting espresso parameters, you still need to judge whether the flavor is appropriate by making a latte (Americano).

Some coffee shops use different espresso standards for making lattes and Americanos. The coffee base for lattes might extract less coffee liquid because the later segments of coffee liquid have lower concentration and taste bitter-sweet. With less of this portion, the texture after adding milk is fuller, and the sweetness is better. For Americanos, normal extraction or extracting more coffee liquid is used because Americanos are essentially diluted espresso, so a more complete extraction will make the Americano coffee have more flavor (as long as the espresso doesn't have burnt, bitter, or astringent flavors, the resulting Americano won't either).

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473