<p>One possible answer: it isn't a question of coarse grind being better than medium in a French press, or a uniform grind producing better taste than a non-uniform one. They have different objectives and different effects on the flavor profile.</p>
<p>A coarse grind or non-uniform particle size has a &quot;flatter&quot; distribution curve of extracted flavors. As the extraction progresses, only a fraction of the coffee is contributing over-extracted flavors, and a different fraction of the coffee is contributing more of the light-extraction flavors. So the extraction can add a little bitterness without overwhelming the taste, and the range of extracted flavors stays in more of a balance.</p>
<p>Coarse grind can produce good-tasting coffee with a broader or fuller flavor profile. You can produce good-tasting coffee with a similarly broad/full flavor profile using a non-uniform smaller particle size, but it's harder to control. The particle size can be non-uniform, but the distribution needs to be consistent from grind to grind to zero in on the extraction.</p>
<p>With a very uniform particle size, all of the coffee is being extracted to the same degree.  The distribution of flavors has a peak, which moves across the spectrum from light extraction flavors to over-extracted flavors, and all of the coffee follows that peak.  The peak is what you control when you vary the extraction parameters.  If the peak moves into over-extracted territory, all of the coffee is contributing those flavors and it overwhelms the taste.</p>
<p>A uniform grind size allows targeting a more specific desired flavor profile.  That highlights a desired portion of the flavor distribution rather than producing simply good-tasting coffee with a full flavor.  This can bring out flavors that distinguish specific kinds of beans.</p>

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2022-11-02T20:06:45.200Z
2022-11-02T20:06:45.200Z
fixer1234
<p>A uniform coarse grind makes it is easy to filter, which means you can use simpler filtration and still avoid having fine bean particles in your final brew.  A fine grind french press would taste terrible if you use most pots because they do not filter out enough of the particles from the final brew you drink.</p>
<p>Additionally, there is much less precision required in terms of time, because a coarse ground soaked for a longer period of time has a wider margin of error compared to the margin of mere seconds when using a finer grind.  Possibly due to oxidation becoming a factor during longer brews.  Even if your French Press had a great filter to address the filtration, you would find yourself having to have a very narrow range of timing to ensure it is not over-extracted or under-extracted.</p>

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2022-11-02T19:00:34.497Z
Some good logic here, but a few thoughts: 1. You can go to medium grind in a French press and the mesh still filters it. James Hoffmann's technique uses a grind closer to medium, and uses settlement to get the fines, then uses the screen as a filter at the top rather than plunging it, and doesn't pour the last dregs. And he uses even longer than typical timing. Suggests that medium grind should be better than coarse grind for French press. 2. The timing margin of error would become a problem if you tried a fine grind in a French press. (cont'd)
fixer1234
CC BY-SA 4.0
2022-11-02T19:00:39.787Z
But a medium grind wouldn't (even a med-fine in an AeroPress is very manageable). 3. The reason less precision is required with a coarse grind is because the over- and mixed-extraction is already part of the brewing method. That's kind of the corollary of the question--if that works great for French press, why the need for uniform particle sizes?
fixer1234
CC BY-SA 4.0
2022-11-02T18:15:51.973Z
2022-11-02T18:15:51.973Z
Steve V
<p>The purpose of a uniform particle size is to get the same level of extraction from all of the coffee.  If there was a big difference in particle size, the small particles would be over-extracted by the time the big particles get well-extracted, or the big particles would get under-extracted by stopping when the small particles are properly extracted.  And the brew ends up a mix of extraction levels rather than a targeted level.</p>
<p>The difference is because it takes time for water to soak into the interior of the particles and leach out the solubles.  The farther the center of the particle is from the surface, the longer it takes.</p>
<p>A coarse grind is a different configuration of the same issue.  Water needs to go through the bean material near the surface to get to the bean material at the center.  So you have the same action as large and small particles, only within the same particle.  Bean material near the surface will get over-extracted in the process of extracting from bean material in the center.</p>
<p>With a small particle size, the bean material in the center isn't far from the surface.  So extraction should be very uniform within the particle as well as between particles.  And with a small particle size, extraction time is much faster.  That doesn't preclude any brewing methods, like French press; you would just brew for a shorter time.</p>
<p>If it is so important to start with a uniform grind size, why would a coarse grind ever be desirable?</p>

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2022-11-02T02:14:06.637Z
This logic would say to always grind as fine as possible, but the mechanics of brewing methods tend to have minimum particle sizes that work with the brewing hardware.  There's also the consideration of accurately controlling the brew time; the shorter the time, the bigger the effect of imprecision. So the question just relates to coarse grind.
fixer1234
<grind-size>
Why is coarse grind ever better?
fixer1234
# Why is coarse grind ever better?

(Asked by: username_0 on 2022-11-02)

The purpose of a uniform particle size is to get the same level of extraction from all of the coffee. If there was a big difference in particle size, the small particles would be over-extracted by the time the big particles get well-extracted, or the big particles would get under-extracted by stopping when the small particles are properly extracted. And the brew ends up a mix of extraction levels rather than a targeted level.

The difference is because it takes time for water to soak into the interior of the particles and leach out the solubles. The farther the center of the particle is from the surface, the longer it takes.

A coarse grind is a different configuration of the same issue. Water needs to go through the bean material near the surface to get to the bean material at the center. So you have the same action as large and small particles, only within the same particle. Bean material near the surface will get over-extracted in the process of extracting from bean material in the center.

With a small particle size, the bean material in the center isn't far from the surface. So extraction should be very uniform within the particle as well as between particles. And with a small particle size, extraction time is much faster. That doesn't preclude any brewing methods, like French press; you would just brew for a shorter time.

If it is so important to start with a uniform grind size, why would a coarse grind ever be desirable?

**Tags:** grind-size

> **Comments:**
> **username_0**: This logic would say to always grind as fine as possible, but the mechanics of brewing methods tend to have minimum particle sizes that work with the brewing hardware.  There's also the consideration of accurately controlling the brew time; the shorter the time, the bigger the effect of imprecision. So the question just relates to coarse grind.  

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## 2 answers

### Answer by username_0 on 2022-11-02. Score: 3

One possible answer: it isn't a question of coarse grind being better than medium in a French press, or a uniform grind producing better taste than a non-uniform one. They have different objectives and different effects on the flavor profile.

A coarse grind or non-uniform particle size has a "flatter" distribution curve of extracted flavors. As the extraction progresses, only a fraction of the coffee is contributing over-extracted flavors, and a different fraction of the coffee is contributing more of the light-extraction flavors. So the extraction can add a little bitterness without overwhelming the taste, and the range of extracted flavors stays in more of a balance.

Coarse grind can produce good-tasting coffee with a broader or fuller flavor profile. You can produce good-tasting coffee with a similarly broad/full flavor profile using a non-uniform smaller particle size, but it's harder to control. The particle size can be non-uniform, but the distribution needs to be consistent from grind to grind to zero in on the extraction.

With a very uniform particle size, all of the coffee is being extracted to the same degree. The distribution of flavors has a peak, which moves across the spectrum from light extraction flavors to over-extracted flavors, and all of the coffee follows that peak. The peak is what you control when you vary the extraction parameters. If the peak moves into over-extracted territory, all of the coffee is contributing those flavors and it overwhelms the taste.

A uniform grind size allows targeting a more specific desired flavor profile. That highlights a desired portion of the flavor distribution rather than producing simply good-tasting coffee with a full flavor. This can bring out flavors that distinguish specific kinds of beans.


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### Answer by username_1 on 2022-11-02. Score: 1

A uniform coarse grind makes it is easy to filter, which means you can use simpler filtration and still avoid having fine bean particles in your final brew. A fine grind french press would taste terrible if you use most pots because they do not filter out enough of the particles from the final brew you drink.

Additionally, there is much less precision required in terms of time, because a coarse ground soaked for a longer period of time has a wider margin of error compared to the margin of mere seconds when using a finer grind. Possibly due to oxidation becoming a factor during longer brews. Even if your French Press had a great filter to address the filtration, you would find yourself having to have a very narrow range of timing to ensure it is not over-extracted or under-extracted.

> **Comments:**
> **username_0**: Some good logic here, but a few thoughts: 1. You can go to medium grind in a French press and the mesh still filters it. James Hoffmann's technique uses a grind closer to medium, and uses settlement to get the fines, then uses the screen as a filter at the top rather than plunging it, and doesn't pour the last dregs. And he uses even longer than typical timing. Suggests that medium grind should be better than coarse grind for French press. 2. The timing margin of error would become a problem if you tried a fine grind in a French press. (cont'd)  
> **username_0**: But a medium grind wouldn't (even a med-fine in an AeroPress is very manageable). 3. The reason less precision is required with a coarse grind is because the over- and mixed-extraction is already part of the brewing method. That's kind of the corollary of the question--if that works great for French press, why the need for uniform particle sizes?  

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