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Why Coffee Machine Coffee Isn't Strong & Why Espresso Needs Daily Calibration

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, "Why do we need to calibrate espresso extraction parameters every day? It's the same batch of coffee beans, the same machine, the same extraction plan, so shouldn't everything remain constant?" Actually, things do change! You might not notice it in just a day or two, but by the time you do discover the problem, who knows how many customers have already been served unpleasant coffee~

"Why do we need to adjust espresso extraction parameters every day? It's the same batch of coffee beans, the same machine, the same extraction plan—how could there be any other changes?" Well, there really are! You might not notice it in one or two days, but when you finally realize it, who knows how many customers have already tasted bad coffee!

Don't Assume Your Coffee Machine & Grinder Stay the Same!

Most people view these machines as fixed objects—just perform routine cleaning and maintenance, and problems rarely arise. This is certainly true when the machines are new! However, components like espresso machine brewing pipes, brew heads, steam boilers, pressure valves, and relief valves are all in daily operation. They experience varying degrees of wear every day (so subtle that you can't detect it), until suddenly one day they fail!

These parts often show warning signs before breaking down. For instance, abnormal water output during brewing, insufficient water temperature, or inadequate extraction pressure will all be clearly reflected in the taste of the extracted espresso, such as uneven extraction or under-extraction.

Similarly with espresso grinders—the burrs grind day after day and also experience continuous wear. This can result in coffee grounds becoming coarser at the same setting, or producing more fine particles. These conditions will also manifest in the taste of the extracted espresso, such as sharp sourness and lack of flavor, or noticeable bitterness.

Even with the Same Coffee Beans, Their Condition Changes Daily

The state of coffee beans changes every single day! FrontStreet Coffee ships all coffee beans within 5 days after roasting. During the roasting process, coffee beans generate a large amount of carbon dioxide inside, which continues to release naturally in the days following roasting. What we call the "tasting period" is actually the effective degassing period of the coffee beans. This carbon dioxide helps preserve/maintain flavor, but as the number of storage days increases, the release of carbon dioxide also carries away some coffee flavors until it's depleted, at which point the coffee beans lose freshness and flavor.

In other words, coffee bean flavor is constantly changing, especially after an overnight period, where the flavor state changes more noticeably.

FrontStreet Coffee's espresso blend beans all use medium-dark roast, so the coffee beans contain more carbon dioxide than medium-light or medium-roasted coffee beans. This carbon dioxide affects the entire espresso performance during extraction. The fresher the espresso beans, the more carbon dioxide they contain, which slows down water flow during extraction, prolongs extraction time, and ultimately presents very rich crema, affecting the overall mouthfeel. In severe cases, over-extraction may occur. When the coffee beans' carbon dioxide emission is mostly complete and the flavor has significantly diminished (starting to lose freshness), water flow naturally speeds up, shortening extraction time. The final espresso will present thin crema and the mouthfeel will become weak and bland.

How to Adjust Espresso Extraction Parameters Daily

Use the previous day's extraction parameters for the first espresso extraction of each day. Since each blend coffee bean has different extraction parameters, FrontStreet Coffee will use the daily production Warm Sun Blend coffee bean extraction parameters as an example. The Warm Sun Blend is composed of Honduras Sherry and Yirgacheffe Natural Red Cherry, with flavors of chocolate, berries, cream, vanilla, and wine-like notes. (When adjusting daily parameters, don't casually change the grind setting or espresso machine extraction parameters, unless you can no longer adjust the coffee flavor expression by increasing or decreasing the coffee grounds and extraction ratio.)

FrontStreet Coffee's yesterday espresso extraction parameters were 20g of coffee grounds to extract 40g of coffee liquid, with an extraction time of 28-29 seconds. Today, after replenishing coffee beans in the bean hopper and using the same parameters for extraction, the resulting espresso had a heavy dark cocoa flavor, thick crema, lacking wine-like notes and gentle acidity. Another extraction was performed using the same extraction plan to confirm consistency and rule out human operational issues (such as uneven distribution or imbalanced tamping).

After confirming it wasn't a human operational issue, adjustments were made. The slightly concentrated situation might be because the bean hopper was replenished with beans, providing more gravitational pressure on the burrs during grinding, resulting in more uniform cutting of the coffee beans and more uniform, fine particles. For this situation, FrontStreet Coffee decided to reduce the dose by 0.3g today, extracting 40g of coffee liquid with 19.7g of grounds, with an extraction time of 26-27 seconds. After adjusting the parameters, the crema was very rich, revealing the wine-like notes of the Sherry coffee beans, the gentle berry acidity of the Red Cherry coffee beans, an overall vanilla cream-like smoothness, and a nutty chocolate aftertaste.