Hario Grinder Coarseness Adjustment Guide for Pour-Over Brewing

Introduction to Hario Grinder Settings

Approximately 40% of visitors to this blog arrive while searching for information about Hario grinders, with most wanting to know how to adjust the grind settings. Therefore, I've created a simple comparison to help those considering purchasing this machine understand what to expect.

Testing Subject

Today's test subject is the premium espresso blend from FrontStreet Coffee.

Adjustment Process

First, remove the grinder handle, leaving only the bottom gear.

Adjust the gear height to the desired position, then replace the catch.

Once the handle is reattached, you can begin grinding beans.

Grind Settings Analysis

Upon careful examination, the gear offers eight full rotations of adjustment range. However, when set to the highest point, beans can fall through without being ground, which is impractical. Therefore, I only tested five rotations starting from the lowest setting.

Unroasted beans before grinding.

Five groups of ground beans ready for comparison.

At the lowest setting, the gap is extremely narrow, making it nearly impossible to grind beans effectively. It feels more like peeling the coffee beans than grinding them. I gave up after a few attempts, but you can see the resulting powder is exceptionally fine. Those with patience might want to experiment with this setting.

Grind Setting Variations:

Lowest setting plus one rotation:

Lowest setting plus two rotations: The particles begin to become coarser.

Lowest setting plus three rotations:

Lowest setting plus four rotations: The beans are crushed to approximately one-quarter of their original size.

Since I couldn't find appropriate markers at the time, these photos don't include a scale reference, but the difference in powder fineness should still be visible. The gear catch design allows for fine adjustment in increments of one-sixth of a rotation.

For my siphon brewing method, I typically use the setting at the lowest point plus one and two-thirds rotations. The principles of most manual grinders are quite similar. Everyone should adjust their grind settings according to their brewing method and preferred taste profile.

The Espresso Roast blend I tested this time consists of mixed beans with rich fruity aromas. At first taste, there's a noticeable earthy flavor, but the aftertaste left on the tongue is pleasantly sweet, which I quite enjoyed.

Environmental Factors and Grind Adjustment

Humidity changes are also factors that affect grind settings. When humidity is relatively high, ground coffee becomes moist quickly. During dosing and distribution, the coffee already has slight moisture content. If using a finer grind setting, the coffee flavor compounds will react with the humid air, becoming muddled and impure. At this point, the coffee grounds are more easily compressed, extending the extraction process and making it easier to extract undesirable flavors, resulting in an overall muddled coffee taste. Therefore, in high humidity conditions, finer grind settings are not suitable; using a slightly coarser grind setting is better. Conversely, in low humidity conditions, coffee grounds oxidize faster after grinding and come into contact with air. If using a coarse grind setting, the combination of coffee ground oxidation and flavor compound changes results in coffee with less extracted flavor, lacking depth and body. Therefore, the grind setting should be appropriately finer. Of course, after adjusting the grind setting, corresponding adjustments to tamping pressure are also necessary.

Different coffee growing regions, varieties, and densities vary, and different roast levels also create differences in hardness, leading to changes in grinding rate and particle size. As a result, previous grind settings, dose amounts, and tamping pressure may no longer be appropriate. This is similar to how you can't force your feet into shoes that don't fit. That's why many domestic cafés use dedicated grinders for specific beans to ensure consistency in grinding results.

Therefore, my final recommendation is: with a fixed coffee bean, first determine the dose amount, then find the appropriate grind setting, and finally use a relatively consistent pressure to develop your technique. Consistency should be the highest priority, but I believe this point also increases variability. When you use a specific bean type, find the right setting, determine the dose amount, and use a comfortable tamping pressure to produce a decent espresso, you've essentially accomplished the main goal. The reason I say adjusting tamping pressure can increase variability is because grind settings, dose amounts, and the beans themselves will all have minor variations due to environmental conditions. These variations can mostly be compensated for through adjustments in tamping pressure to achieve consistent extraction results. This is the variable with the most flexibility because our bodies are not machines - tamping pressure depends on feel, which beginners typically haven't developed yet.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473