Wet Coffee Pucks in Espresso Making – Should You Be Concerned?

When investing in a professional espresso machine costing anywhere from hundreds to thousands of dollars, monitoring brewing quality through indicators like spent coffee pucks is essential. However, a wet coffee puck isn’t always a sign of machine problems or poor brewing technique.

Understanding Wet Coffee Pucks

During espresso extraction, water travels from the boiler through the group head and shower screen before reaching the coffee. When brewing begins, water fills the space between the shower screen and coffee bed before percolating through the grounds. When extraction stops and pressure releases, the remaining water has nowhere to go except into the spent coffee puck.

This explains why coffee pucks always retain some moisture after brewing. In fact, some moisture in the puck is completely normal and even necessary for even extraction.

When to Be Concerned

Only worry when your puck is excessively wet and accompanied by other unusual signs. The most common issue is under-dosing – for example, using 14g of coffee in a portafilter designed for 18g. In this case, the larger headspace will hold more water, resulting in an unusually wet puck.

Additionally, if your espresso tastes off (weak, overly bitter, or sharply acidic) along with a wet puck, this could indicate:

• Grind size issues (too coarse or too fine)
• Uneven tamping
• Poor coffee distribution in the portafilter

When investing in a professional espresso machine that costs from tens to hundreds of millions of dong, it is necessary to monitor the quality of the brew through signs such as coffee grounds. However, wet coffee grounds are not always a sign of a problem with the machine or brewing technique.

Simple Solutions

First, focus on the taste of your espresso shot. If it tastes great, don’t worry too much about puck moisture. However, for improvement:

Use a scale to ensure proper dosing for your portafilter. Maintain an appropriate headspace between the coffee surface and shower screen – enough for even water distribution but not excessive.

Clean your machine regularly, especially the shower screen and group head, to ensure even water flow. This not only improves brewing quality but also extends the life of your investment.

Remember, some moisture in the coffee puck is normal and beneficial for extraction. Instead of fixating on puck appearance, let the taste of your espresso be the primary measure of your brewing technique.

Images used in this article were collected by 43 Factory Coffee.

Frequently Asked Questions

Does the coffee puck need to be dry after brewing?

No, a certain amount of moisture is completely normal and actually necessary for even extraction. Professional baristas understand that a slightly wet puck is often a sign of proper brewing.

Why is my puck sometimes wetter than usual?

The most common cause is under-dosing – using too little coffee for your portafilter size. For instance, using 14g in a basket designed for 18g. The larger gap between the coffee and shower screen holds more water, leading to a wetter puck.

How can I tell if a wet puck indicates a technical problem or is normal?

Focus on your shot quality – if your espresso tastes great with proper extraction time (typically 25-30 seconds), any puck moisture is likely normal. However, if your coffee tastes off (weak, bitter, or sour) and your puck is wet, you might have a technical issue to address.

Should I adjust my machine if I’m getting wet pucks?

Not necessarily. Start by checking your dosing and technique before making any machine adjustments. Regular maintenance according to your machine’s manual is usually sufficient. Most high-end espresso machines are calibrated correctly from the factory.

Does puck moisture affect espresso taste?

No direct correlation exists. The puck’s moisture is a result of the brewing process, not a cause of taste issues. Professional coffee shops worldwide focus on shot quality metrics like extraction time, shot volume, and taste rather than puck appearance.