Coffee Grinders Leave Up to 20% of Grounds Inside, Study Finds

A recent comparison of eight coffee grinders revealed significant disparities in performance, with some machines retaining as much as 20% of ground coffee beans internally. The Korea Consumer Agency's evaluation, detailed in their "Coffee Grinder Quality Comparison Results," highlighted differences in grind particle range, grinding time, and noise levels among the tested models.

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The Korea Consumer Agency announced the results of its 'Coffee Grinder Quality Comparison Results' on the 13th, which tested and evaluated the quality and safety of eight coffee grinder products sold on the market.

The study examined both conical burr grinders (De'Longhi, Breville, Cuckoo Electronics, Hario) and flat burr grinders (Braun, Feyman, Comax, Delico). Hario offered the widest grind range (79-2614μm), suitable for various brewing methods, while Braun had the narrowest (428-1388μm). A narrower grind range means less versatility for different coffee preparations, from espresso to cold brew.

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Hario products had the widest range of 79 to 2614μm, while Braun products had the narrowest range of 428 to 1388μm.

When tested for medium grind settings for hand-drip coffee, Comax produced a weaker brew, Feyman was average, and the remaining six were strong. Cuckoo Electronics, Braun, and Delico consistently produced strong coffee even at the coarsest settings. The amount of coffee grounds left inside the grinder after use also varied greatly, with Delico and Feyman retaining 19-20% at the finest setting, while Comax retained only 1%. However, at medium settings, all grinders left less than 4% of grounds.

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Delico products had the highest residual coffee grounds at 20%, and Feyman products also had 19%. In contrast, Comax products had the lowest at 1%.

Grinding times differed by up to 4.1 times between models. Comax was the fastest at the finest setting (17 seconds), while Hario took the longest (60 seconds). At the coarsest setting, De'Longhi was fastest (8 seconds) and Braun slowest (33 seconds). Noise levels ranged from 77dB to 83dB, comparable to a vacuum cleaner. While energy consumption varied, the cost difference per use was negligible due to short operating times. All tested products met safety and certification standards.

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The time it took to grind 20g of beans once varied by up to 3.5 to 4.1 times depending on the grinding setting.