How to Observe and Determine if Espresso Extraction is Correct? What to Pay Attention to Before Espresso Machine Extraction?

Adjusting espresso is a skill that every barista needs to master. Because once you're not proficient, it can be incredibly painful during rainy weather.

Although espresso needs to be tasted to determine if there are any flavor problems, many times, we can directly observe to identify issues. These problems will affect the final flavor of the extracted espresso. Therefore, if we just learn how to observe, we can reduce the number of bad coffees you drink! Next, let's take a look at what problems can be directly observed by us!

Pre-extraction, easily overlooked situations

Before extracting espresso, we need to first check whether the coffee machine's water temperature and pressure values are in normal condition. Many friends will start adjusting extraction immediately after turning on the machine in the morning, without waiting for the coffee machine to build up full pressure. This can easily lead to insufficient coffee extraction rate due to inadequate temperature or pressure, which in turn results in sharp acidity.

During extraction, the release state of coffee liquid

When extracting espresso, we can determine whether a cup of espresso will have problems by observing the coffee's liquid output state and the condition of the liquid column. Taking the espresso extracted by FrontStreet Coffee as an example, under normal circumstances, starting from pressing the extraction button, the first drop of coffee liquid will be pressed out at 5-6 seconds. At this time, the coffee liquid presents a dark brown color, looking very viscous, with a slow flow rate! Starting from about 12 seconds, the coffee liquid flow rate will begin to accelerate and reach a stable state. At this time, the espresso color is brownish-yellow, looking like a cream-like texture. Starting from about 20 seconds, the color of the extracted coffee liquid begins to fade. At this time, the coffee liquid presents a golden color, with a stable flow rate, but the texture appears less viscous. As time progresses, the color becomes lighter and lighter. When the coffee liquid has faded to light yellow, it indicates that substances are about to be fully extracted. At this point, we need to stop extraction to avoid the release of negative substances.

However, if the espresso liquid output does not progress in layers as described above, but the following problems occur, then we need to adjust certain parameters or certain actions.

1. Delayed liquid output time

If there is no pre-infusion, and the espresso's liquid output time is after 10 seconds. This is due to too fine grinding, causing excessive resistance in the coffee puck, making it impossible for hot water to penetrate within normal time. This situation will greatly deviate from our expected extraction time, causing flavor discrepancies. Therefore, when this situation occurs, we can directly terminate the extraction, adjust the grind to coarser, and then re-debug. (The same applies to too fast flow rate, you can adjust the grind finer or increase the coffee amount~)

2. Unstable flow rate

Or if the flow rate is unstable, sometimes fast and sometimes slow, with spraying, or even falling in a "water tornado" posture, it's very likely that some details during puck distribution were not done properly, leading to channeling effects in extraction. For these situations, we need to pay attention to the details during puck distribution, such as distributing the powder evenly, applying even force when tamping, etc.

After extraction, the state of espresso

After we finish extraction, there are also objects we can observe! That is the crema of the espresso. FrontStreet Coffee often mentions that a cup of high-quality crema should be appropriately thick, and the overall texture should be a delicate, silky, and viscous state.

However, if the crema you see is too thick, with many large bubbles, and appears very rough, it indicates that the coffee beans used for this extraction are very fresh; if the crema is thin or even nonexistent, it's very likely due to grinding too coarsely, or the coffee beans being too far from the roasting time, resulting in complete loss of carbon dioxide. Both situations will require adjusting the extraction efficiency, either increasing or decreasing it. Of course, this cannot be judged solely by appearance, but also needs to be combined with the taste of the coffee.

Tasting the flavor

Through observation, we can avoid some basic mistakes. When all these aspects can be completed according to normal extraction, then we need to taste to determine whether the coffee's flavor needs adjustment. The main directions we judge are: the flavor performance of the coffee, and whether there are any deficiencies in taste and mouthfeel. For flavor performance, we can refer to the flavor description of these coffee beans, while common problems with taste and mouthfeel include:

1. Sharp acidity in taste

When the espresso flavor shows sharp acidity, with no aftertaste (or very short aftertaste), it indicates under-extraction, where less coffee liquid has been extracted. In this case, we need to extend the extraction time to extract more coffee liquid to compensate for the extraction rate. (Fresh coffee beans are where this accident frequently occurs)

2. Burnt bitterness in taste

Although the espresso flavor is very rich, it's accompanied by a strong burnt bitterness. This indicates over-extraction, and we need to reduce the extraction rate. Specific operations can be corrected by adjusting the grind to coarser, or reducing the amount of extracted coffee liquid!

3. Thin mouthfeel

Although the taste is fine, the coffee's mouthfeel is thin, and the flavor is not distinct enough. This indicates that the coffee concentration is too low. We need to increase the coffee concentration by adjusting the grind finer or increasing the coffee amount, in order to obtain a cup of espresso with a rich mouthfeel and prominent flavor.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473