# Bean roast to grind setting



## RichD1 (Oct 17, 2016)

As a guide when dialling in the grinder for a different bean do you go finer or coarser for a darker bean.

I've just opened some Columbian and notice that it is quite dark compared to a Malabar.

Richard


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## u2jewel (Aug 17, 2017)

RichD1 said:


> As a guide when dialling in the grinder for a different bean do you go finer or coarser for a darker bean.
> 
> I've just opened some Columbian and notice that it is quite dark compared to a Malabar.
> 
> Richard


Darker = Coarser.. (very, very generalised though..)


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## DavidBondy (Aug 17, 2010)

As those on here that know me will be aware, I only drink very, very dark roasts. I grind relatively finely but have recently (since acquiring a variable speed grinder) found that the grinder speed makes the biggest difference. I have mine set for 380rpm which give me a very consistent grind and my workflow gives me a very consistent pour. If I increase the speed I get channeling. Of course, it is obvious that a darker bean will be much softer than a light one and I do not have the equipment (or the eyesight) to see what the difference in the particle size is.


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## The Systemic Kid (Nov 23, 2012)

DavidBondy said:


> Of course, it is obvious that a darker bean will be much softer than a light one and I do not have the equipment (or the eyesight) to see what the difference in the particle size is.


Darker beans are more brittle than lighter roast - produce more fines when being ground as they shatter.


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## The Systemic Kid (Nov 23, 2012)

Simple test - try grinding lighter and darker roasts in hand grinder - lighter create more resistance as they are softer - darker require less effort because they are more brittle.


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## RichD1 (Oct 17, 2016)

The Systemic Kid said:


> Darker beans are more brittle than lighter roast - produce more fines when being ground as they shatter.


So a finer setting for a lighter bean and coarser for darker beans?

Richard


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## The Systemic Kid (Nov 23, 2012)

Yes.


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## Hasi (Dec 27, 2017)

DavidBondy said:


> As those on here that know me will be aware, I only drink very, very dark roasts. I grind relatively finely but have recently (since acquiring a variable speed grinder) found that the grinder speed makes the biggest difference. I have mine set for 380rpm which give me a very consistent grind and my workflow gives me a very consistent pour. If I increase the speed I get channeling. Of course, it is obvious that a darker bean will be much softer than a light one and I do not have the equipment (or the eyesight) to see what the difference in the particle size is.


I believe this also depends on the amount of beans pushing from above. if the hopper is empty, lighter beans would escape the burrs more easily and keep bouncing back up the hopper door. Especially at higher speeds. Lower speeds and bigger burrs will miss less beans.

I notice this quite a bit on my grinders and try to load a few extra beans so I can keep the grams/second ratio consistent (just for the record: I don't weigh every shot).


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## DavidBondy (Aug 17, 2010)

Hmm. Interesting but of course, I don't have a hopper at all as such. I single dose the weighed beans directly into the burrs.


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## Hasi (Dec 27, 2017)

DavidBondy said:


> Hmm. Interesting but of course, I don't have a hopper at all as such. I single dose the weighed beans directly into the burrs.


ok, that's another story. Nice setup btw









For those working with timers, though, it might make a difference


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## u2jewel (Aug 17, 2017)

DavidBondy said:


> As those on here that know me will be aware, I only drink very, very dark roasts. I grind relatively finely but have recently (since acquiring a variable speed grinder) found that the grinder speed makes the biggest difference. I have mine set for 380rpm which give me a very consistent grind and my workflow gives me a very consistent pour. If I increase the speed I get channeling. Of course, it is obvious that a darker bean will be much softer than a light one and I do not have the equipment (or the eyesight) to see what the difference in the particle size is.


Universal problem amongst all single dosing, if I'm not mistaken. Amongst many compromises single dosers have (talking about users who have modified use for a conventional hopper grinder), not being able to adjust the rpm is one of them. As you are already aware, on any fixed grind setting on these single dosing specialists, changing the rpm of burrs changes the grind distribution profile as well.

Not only that, in single dosing grinder situations, the lack of time spent by the grinds in the burr chamber (chance for grinds to mingle?) and typically no static controllers/grids (meaning no backing up of the grinds in the exit chute, again, Jack of chance to mingle) results in grinds looking extremely nice and fluffy, but somehow very prone to channelling. A very thorough whisking is necessary. Wdt can mean many techniques all leading to redistribution of grinds, but I feel only aggressive stirring/whisking gets rid of channelling. That, or keep the rpm as low as you can possibly accept.



Hasi said:


> I believe this also depends on the amount of beans pushing from above. if the hopper is empty, lighter beans would escape the burrs more easily and keep bouncing back up the hopper door. Especially at higher speeds. Lower speeds and bigger burrs will miss less beans.
> 
> I notice this quite a bit on my grinders and try to load a few extra beans so I can keep the grams/second ratio consistent (just for the record: I don't weigh every shot).


Yes, totally. It is a problem, but only for hopper users. The amount (which =weight of beans) pressing down on the grinder throat should dictate how much weight is exerted on to the beans inside the grinding chamber already.

It probably varies a lot on many factors.. But my 64mm flat burrs suffer greatly from a widened spread of grind particle size distribution. I suspect the tight unimodal peak with a full hopper becomes like a flattish and broader hill when single dosing.. So I use a weight to keep it as consistent as like before


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