Grinder motor size and why it makes a difference

#1: Post by **Kettlebarista** » March 8th, 2016, 4:41 pm

I was curious, if burr size, and rpm's were the same for two different grinders, but one had a larger motor. What is the advantage?

#2: Post by **nickw** » March 8th, 2016, 4:52 pm

Torque.

Primary benefit is when starting under load. Some grinders can stall when grinding lighter roasts.

March 8th, 2016, 4:54 pm

So if you compared a 250w motor to a 500w motor the only advantage would less of a chance of stalling?

#4: Post by **Beezer** » March 8th, 2016, 5:05 pm

More torque and less chance of overheating and jamming.

March 8th, 2016, 5:07 pm

Would you consider a 250w motor underpowered for 64mm burrs?

March 8th, 2016, 5:13 pm

Is this just a thought exercise, or are you comparing specific grinders. Wattage computations do not always translate to real world use. The motor, regardless as to the rated power, needs to be compared to the burr design.

March 8th, 2016, 5:18 pm

A bit of a thought exercise and comparison. I'm trying to learn as much as I can while researching a new grinder to purchase. I guess the two grinders in question would be the:

http://www.eureka.co.it/prodotto/zenith_65-e-2/?lang=en

And:

https://www.seattlecoffeegear.com/rocke ... to-grinder

Thank you

#8: Post by **canuckcoffeeguy** » March 8th, 2016, 5:21 pm

Randy G. wrote:Is this just a thought exercise, or are you comparing specific grinders. Wattage computations do not always translate to real world use. The motor, regardless as to the rated power, needs to be compared to the burr design.

Looks to be related to this:
Rocket's new grinder, the Macinatore Fausto?

For the OP, my general understanding is that flat burrs need to spin much faster than conical burrs. Since flats need to spin fast enough to throw grinds outwards. While conicals rely on gravity for the grinds to drop down.

How this relates to a motor's power is beyond my pay grade. I'll defer to others to comment.

#9: Post by **BaristaBoy E61** » March 8th, 2016, 5:41 pm

Torque.

Greater ability to adjust to a finer grind before starting the motor without jamming once the grind is initiated.

SR

#10: Post by **nickw** » March 8th, 2016, 5:57 pm

canuckcoffeeguy wrote:My general understanding is that flat burrs need to spin much faster than conical burrs. Since flats need to spin fast enough to throw grinds outwards. While conicals rely on gravity for the grinds to drop down.

How this relates to a motor's power is beyond my pay grade. I'll defer to others to comment.

Conical burrs require less torque. It's just simple leverage as the diameter of the cutting surface is smaller.
For instance, comparing a Mazzer robur and major:
- The outside diameter of the robur male conical burr is 49mm, which is the final/fines cutting surface (even though they call it a 71mm burr, which is the female burr OD).
- The major is 83mm for final cutting surface.
Would be similar to increasing the tire size on your truck. It will take more to turn them.

In regards to the original post. I'm not familiar with the Rocket grinder, but it looks a lot like a rebadged Mazzer Mini.