Espresso Extraction Issues Collection! Why Can't Pressure Build Up? Why Won't Espresso Produce Crema?

FrontStreet Coffee's Guide to Common Espresso Extraction Issues

FrontStreet Coffee has received another accumulation of espresso extraction questions in their inbox. While the number of private messages is quite large, the problems are largely similar. So, without further ado! Today, FrontStreet Coffee will compile these issues and provide simple solutions to each one. The article will include corresponding links for those who want to learn more details - you can click through for direct access!

Alright, let's begin our Espresso Extraction Problems 1.0 sharing session!

Common Issue 1: Sour Espresso Despite Using Dark Roast Beans

This is one of the more common questions in our private messages! Many friends use dark roast coffee beans, but the extracted espresso still exhibits sharp, sour flavors! This situation is typically caused by "under-extraction." We need to understand that dark roast coffee is not entirely without acidity. It's just that the proportion of acidity in the coffee is relatively small and gets masked by other flavors. With proper extraction, it tastes like a cup of coffee without noticeable acidity. When coffee is under-extracted, the sweet and bitter flavors that would normally balance the acidity are not sufficiently dissolved. This creates an imbalance in the coffee's flavor profile, with acidity "dominating" the taste - sharp and stimulating.

This situation can be easily resolved by extending the extraction time, adjusting the grind to be finer, or reducing the dose - all of which can increase the extraction rate, allowing flavors to dissolve fully, and preventing the coffee from tasting sharp and sour! [Link to detailed guide]

Common Issue 2: No Crema in Extracted Coffee

Thin or completely absent espresso crema is also one of the common problems. This issue often occurs alongside coffee liquid rushing through during the extraction process. While lighter roast levels and older beans can lead to reduced crema, properly extracted coffee should still have a certain thickness of crema, rather than being thin or completely absent.

So, the problem is obvious - it's caused by grind being too coarse. When the grind is too coarse, the coffee puck cannot provide enough resistance against the high-pressure hot water, making it difficult for the carbon dioxide released by the hot water to be trapped in the oils, forming the golden crema. In this situation, adjusting the grind to be finer is the optimal choice! [Link to detailed guide]

Common Issue 3: No Liquid Output

This problem is the complete opposite extreme of the previous one! When you press the extraction button, but no coffee permeates from the portafilter, and only after ten or even twenty seconds does a drop of black liquid勉强 squeeze out.

This situation is caused by the grind being too fine (small possibility of too much coffee)! The puck's resistance is too great, making it difficult for hot water to break through even with extremely high pressure assistance. Therefore, we can appropriately adjust the grind to be coarser to reduce the puck's resistance. It's worth noting that if no liquid appears for more than 15 seconds without pre-infusion, it's best to cancel the extraction directly, as accumulated pressure can create a risk of machine explosion. [Link to detailed guide]

Common Issue 4: Splashing During Extraction

If you're using a bottomless portafilter, then you probably hate seeing coffee liquid splattering and spraying irregularly during extraction. Not only does this easily lead to flavor deviations, but coffee liquid also gets everywhere, requiring extra cleaning effort!

This situation is a phenomenon caused by channeling effects. Water, being inherently "lazy," automatically flows to areas where it can move easily. When it finds larger gaps or lower density areas in the coffee puck that are easier to pass through, it concentrates its flow through these gaps, leading to uneven extraction. There are many factors that cause channeling, such as uneven distribution, coffee clumping, etc., all of which we can address through corresponding solutions. [Link to detailed guide]

Common Issue 5: Pressure Won't Build Up

Pressure is one of the important extraction parameters for espresso. Under normal circumstances, the pressure gauge will continuously maintain a value above 9bar during the extraction process. If it's far below this range and won't build up, then similarly, this is caused by insufficient resistance from the coffee puck.

The occurrence of this situation inevitably means you cannot extract a properly flavored, high-concentration coffee! So, if you want to obtain a standard, delicious espresso, it's best to increase the puck's resistance by adjusting the grind finer or modifying the dose. This way, pressure can build up, and the extracted espresso will not only have the appropriate extraction rate but also be sufficiently concentrated! [Link to detailed guide]

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