# hopper vs single dosing and effect on grinder settings



## dsc (Jun 7, 2013)

I thought I'd start a thread to discuss how dosing methods affect grinder settings. I've heard about and experienced first hand how a full hopper can affect what setting you grind on to get a good extraction, the rule seems to be having to grind finer when single dosing vs hopper dosing. This means:

- less fines produced when single dosing

- more fines produced when dosing with some weight behind the beans

Any ideas why the above happens?

Regards,

T.


----------



## Mrboots2u (May 10, 2013)

Here is one roaster opinion of the effect of single dosing

worth introducing to then debate .

http://londiniumespresso.com/blog/single-dosing-forget-it


----------



## dsc (Jun 7, 2013)

To me that makes no sense, it's physically impossible to get large chunks of coffee past the fine grinding stage of the burrs. Remember, the gap between the burrs is fixed, assuming of course all is aligned properly. You can on the other get smaller particles past the fixed gap and I'd be more willing to believe that more weight behind the beans somehow produces a large number of small particles.

Regards,

T.


----------



## grimpeur (Oct 18, 2013)

dsc said:


> To me that makes no sense, it's physically impossible to get large chunks of coffee past the fine grinding stage of the burrs. Remember, the gap between the burrs is fixed, assuming of course all is aligned properly. You can on the other get smaller particles past the fixed gap and I'd be more willing to believe that more weight behind the beans somehow produces a large number of small particles.
> 
> Regards,
> 
> T.


As you say Tom, the gap is fixed. I agree that as long as a good quality burr set is used, the burr mounting is rock solid and the shaft has next to no runout then the chances of this happening should be greatly reduced.

However, I have noticed that, occasionally, a few large chunks do manage to get through, contrary to what I have just said. It is interesting to note the geometry of these chunks. Very flat with a thickness similar to the diameter of the majority of the grounds surrounding. I theorise that these "flat" particles manage to slip through the gap burr gap due to this geometry! They are few and far between though. That being said, I don't dedicate much time examining my ground coffee! I'll leave that to them professionals, experts and right honourable members over at Home Barista









The very nature of coffee beans and the manner in which they are broken down in a conical grinder has an inherent random element, which of course can be reduced by good beans, well roasted and ground by a high quality device.

Does that make sense?


----------



## dsc (Jun 7, 2013)

It does indeed grimpeur, although as you say the chance of long thin particles moving through the gap in the burrs is rather slim.

I think this needs a bit more testing...

Regards,

T.


----------



## GlennV (Mar 29, 2013)

I've done some testing on this. When single dosing you need to set the grinder significantly finer to get the same shot timing. However, having done that then, in the case of a large conical (Brasilia MC) I couldn't distinguish either visually or by taste between single dosing or using the hopper. Others have reported similar findings. However, doing the same experiment with a large flat burr grinder (75mm MDL) the difference was clear - and using the hopper was superior. This second point doesn't seem to be so generally accepted, but when I posted this on HB I got a number of PMs from people saying they'd found the same thing. Anyway, this is why I use a large conical. At its best, the MDL produced as good a shot, but the conical is so much easier to live with.


----------



## Charliej (Feb 25, 2012)

dsc said:


> I thought I'd start a thread to discuss how dosing methods affect grinder settings. I've heard about and experienced first hand how a full hopper can affect what setting you grind on to get a good extraction, the rule seems to be having to grind finer when single dosing vs hopper dosing. This means:
> 
> - less fines produced when single dosing
> 
> ...


Tom this seems a little counter intuitive to me, surely if for single dosing you need to set the burr gap closer than for a full hopper then more fines will result from the finer grind level anyway? If you have a more consistent pressure over the beans as they enter the grind chamber and as a result your grind level can be coarser then less fines should in theory be produced. I know that when I moved from using a small 52mm lens hood mini hopper to the 58mm one which holds another ~80-90g of beans the result was faster grinding times, a coarser grind needed( I nutate anyway so may be grinding more coarsely than most) and the results in the portafilter look far better, even with the Coffee Compass Monsoon Malabar Hit I'm not getting any clumps or issues with static unlike one or two others and in the cup everything seems to taste a little better since swapping over.

Tom going a little bit off topic here, could you possibly take a look at the thread I started regarding the RR55 in the video sub forum as I think your input on that may be useful.


----------



## dsc (Jun 7, 2013)

By fines I meant particles smaller than the gap between the burrs. It's either what I said above, or going the other way, there's more bigger particles somehow getting through the burrs when single dosing, but I fail to see why. I understand there's a slim chance of getting long thin parts through the burr gap, but I wouldn't say it's enough to force one to grind 2-3 notches finer when single dosing.

I was thinking that maybe a full hopper will force more beans in between the burrs and thus push them apart, but that would result in a coarser grind and having to grind finer with a hopper, makes no sense.

Regards,

T.

PS. will have a look at the other thread


----------



## Charliej (Feb 25, 2012)

I would have thought that when single dosing the inevitable occurrence of some popcorning would lead to more irregular "chunks" of bean and more likelihood of odd shaped particles being produced plus the fines that happen as a result of smashing rather than grinding getting through the burrs?


----------



## Piccolo Espresso (Feb 25, 2014)

Just messing around after service yesterday.Random blend,single dose, Ek on finest setting, 14.2g in 31g out. pre-infusion 6 secs. Tds 8.6 ext yield 18.8.

Robur empty. Fill collar,same beans, No beans in hopper . Grind setting not properly dial in. Manually pulse through to 14.2g in, 31g out. 1 sec pre ...too quick. Tds 9.2 ext yield 20. tasted better. shocked.

That said, Ek fitted with coffee burrs not turkish. Perger prefers longer extractions to increase ext yield. The robur is better at normale ratios not longer.

More experiments needed !


----------



## bronc (Dec 10, 2012)

Anyone with a refractometer tested single dosing vs hopper?


----------



## GlennV (Mar 29, 2013)

Yep. No difference. (This was with two identical large conicals, tested side by side).


----------



## coffeechap (Apr 5, 2012)

GlennV said:


> Yep. No difference. (This was with two identical large conicals, tested side by side).


On conics


----------



## GlennV (Mar 29, 2013)

Indeed.

I did try to do this test with flats, picking up a super lusso to go with my super caimano (basically the same grinder of course), but couldn't get enough consistency when single dosing for the test to make sense.


----------

