This question crops up again and again, and many people will swear that you must have a conical grinder.
You can read our view on the matter below.
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Received: Fri, 18 Feb 2011 01:16:47 -0800 (PST)
Subject: Re: Shipping rate query for Mazzer Robur Electronic
From: LE_G
Date: Fri, 18 Feb 2011 09:16:35 +0000
To: Barry Goh <@hotmail.com>
Barry
Is there a taste difference between conical and flat burrs when both grinder=
s are cold? Yes, but that isn't the reason mazzer developed and sell the Rob=
ur.
Mazzer sell the Robur because it heats up more slowly when grinding large vo=
lumes of coffee. Why does it heat up more slowly? Because of the conical bu=
rrs? No! because it is turning at 425rpm instead of 1450rpm on 50Hz electric=
al supply. So as an engineer you have reduced the rate at which the grinder=
overheats because the burrs are now turning much slower. Now the problem i=
s the grinder grinds coffee too slowly! What to do? Increase the circumferen=
ce of the burrs so the distance travelled by the burrs in a given time perio=
d is the same as it was before you slowed the motor down. Now the grinder w=
on't turn as the motor doesn't have enough torque to turn the larger diamete=
r burrs as the resistance presented by the coffee beans between the burrs is=
greater as you can now fit more of them around the increased circumference a=
nd by definition the load is further from the spindle as the radius is now l=
arger and therefore the beans sitting between the burrs exert more torque ov=
er the motor. So you add a significantly larger motor as this is cheaper and=
smaller and than adding a reduction gearbox. Now the grinder turns, grinds l=
ots of coffee, and doesn't heat the coffee too quickly when you've a lot of c=
offee to grind, but there is still a problem! Now that you have reduced the=
spindle speed the grinder doesn't draw the beans into the burrs as nicely s=
o the grinder doesn't feed as evenly as it should, especially with a small m=
ass of beans in the grinder. So you change from flat burrs to conical burrs s=
o the burrs draw the coffee nice and consistently into the grinder. I'm not=
an engineer, but that I think you will find is how we end up with flat and=
conical burr grinders.
I'm 100% sure the manufacturers didn't go, oh the taste of the coffee is a b=
it average with flat burrs, let's make a conical grinder. The problem given=
to the engineers was these grinders running at 1425rpm are heating the coff=
ee far too much when you grind a LOT of coffee. As a result of solving that=
problem they changed from conical to flat burrs. By happy coincidence it t=
urned out that the conical burrs were better at preserving the delicate note=
s present in some coffees. I still suspect this may be due to the slower 42=
5rpm spindle speed rather than the shape of flat versus conical burrs, but I=
lack the knowledge to present a cogent engineering argument so that will ha=
ve to remain as an opinion.
So to conclude, I think anyone who buys a Robur for home use has more money t=
han sense. I have a Mazzer Mini at home. What can I criticise? The taste?=
No! If I wanted to be super critical I'd say it takes too long to fill the p=
ortafilter, and that is the only reason I could think of for moving to a lar=
ger grinder. But would I? No, of course not, complete madness in terms of s=
ize, cost, and just general extravagance, and believe me I'm not averse to a=
little extravagance now and again but even I'd draw the line at a mazzer mi=
ni for home use.
It is true that the grinder is the most important consideration. For home u=
se that means the Mazzer Mini E. It might be different if you say worked fr=
om home and often had business meetings where you needed to make coffee for 5=
-10 people in a hurry, or a family where you entertained large numbers of pe=
ople regularly, but there is nothing in your email to suggest that this is t=
he case.
I will add more shipping costs for Malaysia. No problem with your last ques=
tion either.
Also, do you mind if I paste this email up on my blog as this is a common qu=
estion. I'll remove your contact information, don't worry.
Kind regards
Reiss.
P. +44 20 7193 3901
M. +44 7801 224 520
LondiniumEspresso.com
On 18 Feb 2011, at 04:29, Barry Goh <@hotmail.com> wrote:
> Hello Reiss,
> =20
> Thanks for the info.
> =20
> Do you think that the Robur Electronic is a good idea for an individual to=
use if he will only fix at most 2 cups of coffee a day? Or is it overkill? I=
have read comments on a forum whereby former owners of the Robur E have sai=
d that while it is a great grinder, it produces too much wastage of coffee a=
nd too much coffee gets stuck in its chute etc.=20
> =20
> You see, I am considering a conical grinder because I have read that they s=
upply the best grind for espresso as compared to flat burr grinders, and sin=
ce they say that buying the best grinder is even more important than buying t=
he best espresso machine, I figured that this is probably where I can get th=
e most improvement if I upgrade. Am I right in this idea or is that too simp=
listic?
> =20
> I would also like to know how much would it cost to have you send to me in=
Malaysia a pack of 250g of your roasted coffee? If it is cost effective, th=
en maybe I can order some every month from your shop.
> =20
> Lastly, if I were to order a pack of your coffee along with the grinder, w=
ould the shipping cost for the coffee be obviated?
> =20
> Thanks,
> =20
> Barry Goh
