I read somewhere the words: "a good grinder is to coffee what a good set of speakers is to music".
And if one is to narrow this down to its fundamental ...
speakers should be chosen to suit the genre of music
so burrs can be picked for the type of coffee you intend to make.
So which is better?
Flat or conical ??
The standard answer is:
Flat burrs produce a uniform, single-particle-size grind, ideal for light roasts, clarity and flavor separation in filter coffee, while conical burrs create a bimodal distribution with both coarse and fine particles, resulting in more body and balanced flavors, often preferred for dark roasts, espresso and milk-based drinks.
The graph to the left shows a bi modal particle distribution.
OK Problem solved!!! Or is it?
If I like espresso do all I need is a conical burr?
Should I just use flat burrs if I like my V60?
There are great conical burr grinders like the ZP6 which produce awesome clarity and are designed for filter coffee. There are muddy flat burrs and super clean conical ones.
Of course the answer isn't so simple and I think we are just getting started in working all this out.
It's All about FINES
Both flat and conical burrs produce fines.
Coffee fines are the smallest particles created when grinding coffee beans, essentially cell wall fragments with a very fine, powder-like consistency. They are typically undesirable in pour-over and filter brewing methods because their rapid extraction can lead to bitterness and clogging of the filter.
However, they are considered important for espresso brewing to achieve a better extraction and mouthfeel, though the exact role of fines in taste is still debated.
I think that extra fines are created when the burrs re-grind already ground & compacted beans that are stuck in the burr or from old grinder burrs that don't crush & cut the beans as well as they once did.
I have a cremaloop slow feeder which I think decreases the unevenness of the particles.
A lower RPM on your grinder might also achieve this. I like a lower RPM for filter but a higher for espresso..... that is, I like more fines for espresso.
How they affect your coffee:
Filter Coffee:
Negative effects: Fines can clog the filter, which slows down the brewing process and can lead to over-extraction and a bitter taste.
Positive effects: Fines can also contribute to a cleaner, sweeter cup with a smoother mouthfeel.
Espresso:
Positive effects: Fines increase the surface area of the coffee bed, which is essential for espresso extraction to provide a good taste.
Negative effects: They can cause bitterness and astringency by over-extracting.
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Here's a more detailed coffee burr breakdown:
Flat Burrs:
Flavor Profile:
Flat burrs tend to produce a more uniform particle size, leading to a cleaner and more nuanced espresso shot with greater clarity and separation of flavors.
Best for:
Lighter roasts that benefit from clarity and brightness, and those who appreciate a more defined and layered taste.
Considerations:
Flat burrs can be less forgiving and may require more precise adjustments when dialing in your grind. I think flats create more static that conicals
Conical Burrs:
Conical burrs often produce a thicker, more full-bodied espresso with a more blended flavor profile.
Best for:
Medium to dark roasts that benefit from a bolder, richer taste, and those who prefer a more forgiving grinder.
The coffee burrs flow top to bottom. usually the centre cone spins and the outer ring stays stationary,
but in some designs its the reverse.
Considerations:
Conical burrs can be easier to dial in and may be a better option for beginners or those who prefer a more traditional espresso experience.
One of the main theories why flat burrs have more consistent grind size is because they are easier to align. With Flats, you only need to align them horizontally, whereas conicals need to be aligned in both horizontal and vertical axes.
I don't know if this is true. I think alignment of my
HG-1 is pretty tricky.
Other factors to consider:
Milk Drinks:
For milk-based drinks, the differences between flat and conical burrs can be less noticeable, as the milk tends to mute some of the subtle flavor nuances.
Personal Preference:
Ultimately, the best choice depends on your personal taste preferences and the specific coffee beans you are using. Some people on Reddit prefer the clarity of flat burrs, while others prefer the body and sweetness of conical burrs.
Grinder Quality:
Regardless of the burr type, investing in a high-quality grinder is crucial for consistent result
Flat burrs need a bigger motor that allows them to grind at higher RPM. So a flat burr grinder is usually louder than a conical grinder and has higher grind retention. The higher the RPM, the more static electricity which causes grinds to stick to the burrs.
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My Grinder List.
Some of my fav grinders ... both hand and electric.
As grinders go, these aren't super expensive.
Rather than just have one grinder and swap burrs, I've so far kept to the stock burrs that
the grinders came with and just bought new grinders. (often the cost of a new set of SSP burrs was less than a new grinder).
There is plenty to experiment with, just by doing this.
+1zpresso J-Ultra
(focus: Espresso. 48mm coated conical burr)
(focus: Espresso/pour-over. 38mm Steel conical burrs)
(Focus: Pour-overs. 48mm stainless steel burrs)
(Flat 64mm DLC (Diamond-Like-Carbon) coated burrs)
(Focus: Multi)
Filter & espresso
(Focus: Espresso/pour-over. 58mm flat vertical burrs)
(Focus - filter & espresso)
Focus: Espresso (though it can do filter)
+Kingrinder K6
(48mm Stainless steel conical burr)
(filter & espresso)
(47mm conical black-fusion burrs)
(54mm flat steel burrs. Idle speed:1050 rpm.
Allrounder)
Focus: espresso. 38mm Conical S2C (spike-to-cut) steel burrs
{38mm conical 6 core High-Nitrogen 420 Stainless Steel Supernova Burrs (HRC58)}
I'll probably add to this list in the future ... esp with grinders that use larger burrs.
I think that though bigger isn't necessarly better, the bigger the "canvas" burr designers have to work with, the higher is their opportunity to nail something important.
This doesnt limit to flat burrs. These days you can have large size conicals ...(the Mazzer Robur S uses 71mm conicals).
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Grinder adjustments for Espresso:
Many grinders have a 30-micron increment that can be too coarse for dialing in espresso.
In general, the lower the the microns per click, the better your grinder will be for espresso.
By increasing the threads on the adjustment axle, we can increase the number of available adjustment settings thus making it easier to achieve the very precise grind sizes needed for espresso.
A good grinder adjustment for espresso is a step size that's between 5 and 15 microns per click to allow for precise dialing in the shot. Though some grinders are stepless, offering infinite adjustment. The best adjustment size depends on the specific grinder and the sensitivity of your espresso setup, as a single click can significantly affect your shot time and flavor.
Examples of Grinder Adjustments
Kinu M47: each full revolution having 50 divisions,
resulting in a precision of approximately 5 microns per click
1-Zpresso Jmax: 8.8 microns per click
1-Zpresso J-Ultra : 8 microns / click
1-Zpresso JE-Plus & JX-Pro : 12.5 microns / click
Comandante C40: 25-30 microns per click
Comandante C40 with Red Clix: 15 microns per click
HG-1 by Weber Workshops : 13 microns per click
Pietro by Fiorenzato : 15 microns/click
Timemore C3 (standard not the ESP version): 83 microns per click
Timemore C3 ESP: 23 microns per click
Timemore C5: 31 microns per click
Timemore C5 ESP: 15 microns per click
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"Seasoning" new burrs
Coffee burrs need seasoning to smooth their initial imperfections, leading to a more uniform particle size distribution. This process involves dulling the sharp, inconsistent edges of new burrs, which reduces fines (tiny, unwanted coffee particles) and creates more evenly sized grounds. Seasoning stabilizes grind performance, improves flavor consistency, and increases grinding speed by coating the burrs with coffee oils.
Generally with 64mm burrs and smaller, about 2Kg of beans will season your grinder about 66%.
They won't be close to 100% seasoning till you have ground about 5Kg.
If your burrs are coated , you need even more seasoning... add 50% more ... thus you probably need 7-10kg to do the job properly.
For larger that 64mm, about 5kg will get you to 66% seasoning.
20Kg will get you close to 100%
If these burrs are coated, then you will need to add 50% more to this figure.
Thus for a grinder like my HG-1 with 83mm burrs , I would need about 30kg to properly season it.
( I'm not going to hand grind 30Kg ... I'll just be patient ... they say good things come to those who wait)
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