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

Dialling in espresso is a skill every barista needs to master. When you are not yet fluent at it, a rainy day behind the bar can be genuinely painful.

Espresso ultimately has to be tasted to reveal flavour problems, but much of the time we can spot trouble just by watching, and those signs will shape how the finished shot tastes. Learn to read them and you will drink fewer bad espressos. Let's look at the problems we can catch with our own eyes.

Before Extraction: Easily Overlooked Situations

Before pulling a shot, check that the machine's water temperature and pressure are in a normal range. Many people switch on the machine in the morning and start dialling in right away without waiting for it to build full pressure. That easily leaves the coffee under-extracted because temperature or pressure is too low, and the result is sharp acidity.

During Extraction: How the Coffee Liquid is Released

While extracting espresso, we can judge whether a shot will give problems by watching how the liquid emerges and what the stream looks like. Take the espresso FrontStreet Coffee pulls as an example. Under normal circumstances, from the moment the brew button is pressed, the first drop is pushed out at 5-6 seconds. At that stage the liquid is dark brown, looks very viscous, and flows slowly. From about 12 seconds, the flow begins to accelerate and settles into a steady state; the espresso is now brownish-yellow with a cream-like texture. From about 20 seconds, the colour starts to fade, the liquid turning golden with a stable flow but a less viscous texture. As time goes on it grows lighter and lighter. Once it has faded to pale yellow, the compounds are almost fully extracted, and we need to stop to avoid releasing undesirable substances.

If, instead, the output does not layer as described and the problems below appear, we need to adjust a parameter or a technique.

1. Delayed Liquid Output Time

If there is no pre-infusion and the espresso's first liquid appears after 10 seconds, the grind is too fine, creating too much resistance in the puck so hot water cannot pass through in normal time. That throws the extraction time far off our target and causes flavour problems. When this happens, we can stop the shot, adjust the grind coarser, and dial in again. (The same applies when the flow is too fast: adjust the grind finer or increase the dose.)

2. Unstable Flow Rate

If the flow rate is unstable, sometimes fast and sometimes slow, with spraying, or even falling in a "water tornado," it is very likely that something during puck preparation was done poorly, producing channeling. For these cases we need to mind the details: distribute the grounds evenly, tamp with even force, and so on.

After Extraction: The State of the Espresso

Once the shot is finished, there is still something to observe: the crema. FrontStreet Coffee often notes that a high-quality crema should be appropriately thick, with an overall texture that is fine, silky, and viscous.

If the crema you see is too thick, full of large bubbles, and very rough, the beans used for that shot are very fresh. If the crema is thin or even absent, it is very likely that the grind is too coarse, or the beans are too far past their roast date and have lost all their carbon dioxide. Both cases call for adjusting extraction efficiency, either up or down. Of course, appearance alone is not enough; it has to be read together with how the coffee tastes.

Tasting the Flavour

Observation lets us avoid some basic mistakes. Once all of these aspects come together as a normal extraction should, we still need to taste to decide whether the flavour needs adjusting. We judge mainly two things: how the coffee's flavour performs, and whether there are any shortcomings in taste and mouthfeel. For flavour performance we can refer to the bean's flavour description, while common problems in taste and mouthfeel include the following.

1. Sharp Acidity in the Taste

When the espresso shows sharp acidity with no aftertaste, or a very short one, it points to under-extraction and too little liquid extracted. In that case we need to extend the extraction time to pull more liquid and make up the extraction rate. (Fresh beans are where this accident happens most often.)

2. Burnt Bitterness in the Taste

If the espresso is very rich in flavour but carries a strong burnt bitterness, that indicates over-extraction, and we need to reduce the extraction rate. The usual fixes are to grind coarser or to reduce the amount of liquid extracted.

3. Thin Mouthfeel

If the taste is fine but the mouthfeel is thin and the flavour is not distinct enough, the coffee concentration is too low. We raise it by grinding finer or increasing the dose, so that we end up with an espresso whose mouthfeel is rich and whose flavour stands out.

FrontStreet Coffee Recommendation

Reading a shot is much easier when the bean itself is stable, and that is exactly what FrontStreet Coffee's Classic Blend is for. Designed for espresso and moka pot alike, its standout feature is superb crema: even a beginner on a non-professional home machine can pull dense, fine crema. Built on a traditional Mamba recipe of Mandheling and Brazil, it is full-bodied and mellow — a first-choice bean for home or commercial use, and the one that most often wins as the go-to for newcomers.

If you want a single-origin shot to dial in, FrontStreet Coffee's Brazil Queen Estate SOE is a dependable place to start. It is a Yellow Bourbon with a clean, sweet character, and roasted to a medium-dark level it pulls on an espresso machine into butter cookie, macadamia, and toasted bread creaminess — the low-acid, balanced structure that makes extraction that much more predictable.