How Should a Grinder Be Calibrated? What's the Fastest Way to Adjust an Espresso Grinder?

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Since there are certain differences between each batch of grinders, when FrontStreet Coffee receives a new grinder, it will first calibrate it.

Home Grinder Calibration

Perhaps some people are curious about how to calibrate a grinder at home. Today, FrontStreet Coffee will share with everyone how to calibrate a grinder at home!

First, FrontStreet Coffee will tighten the grinder's adjustment dial to its tightest setting until hearing the friction sound between the burrs. Then, adjust the dial to the manufacturer's recommended grind setting. For our usual pour-over brewing, the grind is approximately the coarseness of granulated sugar, so you can use granulated sugar as a reference! Then, fine-tune according to your preferred pour-over grind size!

The above is a simple method for calibrating a grinder at home. Next, FrontStreet Coffee will share a more professional calibration method with everyone.

Professional Grinder Calibration

Since you have disassembled and reassembled the burrs, you need to recalibrate the grind. The method is as follows:

First, slowly tighten the burrs while powering on the grinder. When you hear the burrs collide, immediately adjust back to avoid burr wear.

For pour-over grinding, we first establish a cupping grind setting. You can purchase a cupping sieve, where the standard cupping grind has a pass rate of 70%-75%. Pour-over grind should be coarser than cupping grind. The pour-over grind used by FrontStreet Coffee has a 58% pass rate.

The above parameters are for reference only!

Espresso Grinder Adjustment

By the way, let me share with everyone how to adjust an espresso grinder!

Preparation Work

First, grinders used for single-origin brewing and espresso grinders are different. Before we begin, confirm whether your grinder is suitable for making espresso. Single-origin grinders have a wider adjustment range and generally produce coarser particles, making them unable to fine-tune or meet the requirements for espresso extraction.

Additionally, when you get a newly purchased bag of coffee beans and plan to adjust the grind, you can first learn the recommended extraction parameters from the seller. Before starting the grind calibration and adjustment, ensure your grinder is clean. Whether by disassembling burrs for cleaning, using brushes, or air blowers, try to thoroughly clean any residual coffee grounds from the grinder.

Grinding Adjustment Process

Step one: Adjust the grinder's dial to its finest setting (considering burr wear in different establishments, we习惯 to start from extreme settings). Then, place the portafilter on an electronic scale and tare it to zero. After dosing, place it on the scale to weigh the target 18g of grounds, distribute them evenly, and tamp with your usual pressure (or use a constant pressure tamper).

After preheating the brew head, proceed with espresso extraction.

Of course, if you don't see the first drop of coffee liquid within 8 seconds of starting extraction, immediately stop the extraction and proceed to the next step—adjust the dial one notch coarser (commercial brand grinders typically have numbered settings; for example, if we previously used setting 1, we'll try setting 2 next). Then we'll weigh another 18g of grounds and attempt espresso extraction again. If obvious over-extraction symptoms persist, we decisively stop extraction, make the dial one notch coarser again, and try extraction once more.

Repeat the adjustment and extraction steps until the dial setting allows espresso liquid to flow normally. Of course, if you're an experienced connoisseur, you can quickly determine the target setting through comprehensive judgment of roast level and particle texture.

Step three: We begin testing extraction yield and tasting the espresso flavor. When espresso flows normally, we prepare a coffee cup, tare it to zero on the scale, and use it to weigh the espresso liquid. Since we're using 18g of grounds, according to espresso extraction standards, the brew ratio should generally be controlled between 1:2-1:2.5 (brew ratio refers to the proportion of ground weight to extracted liquid weight; if we measure 18g of grounds, the target extraction weight will be between 36g-45g).

Step four: Once the espresso flow rate begins to normalize, we start calibrating flavor. Within the extraction time of 20s-25s, can we maintain the extraction state using 18g of grounds to extract 36g-45g of espresso liquid.

If the espresso flavor shows intense burnt, bitter, scorched, astringent sensations and off-flavors, this indicates over-extraction. At this point, you need to make the grinder setting 0.5 notches coarser and test again.

If you notice the espresso flow rate seems fast during extraction, and although you might still get a standard espresso weighing between 36g-45g around 25s, but the flavor is acidic and the body is thin and weak, consider this coffee under-extracted. Then make the dial 0.25 notches finer and conduct another espresso extraction test, timing with a stopwatch.

Yes, this process may sound cumbersome, but it essentially involves controlling the ground dose and target extraction weight to fine-tune the grind setting. First lock in the broad range, then fine-tune the narrow range, searching for the most suitable grind setting.

After repeating the above steps once or twice, you'll approach the target setting.

Step six: At this point, if the espresso extraction flow rate is stable and the crema color is normal, you'll likely achieve standard values. However, if the flow rate is still somewhat fast/slow, grinders with fine adjustment capabilities can make 0.1 setting adjustments. If, unfortunately, you find that the required grind setting falls precisely between two settings, but your grinder doesn't have intermediate settings to choose from, consider adjusting the tamping pressure for calibration.

Using this method for grinder adjustment, you can complete the task using less than 200g of beans. It may seem complex, but because each adjustment follows established principles rather than relying on luck, it saves more time, effort, and cost. Give it a try.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473