This article is part of a series of blogs which are aimed at helping you choose the best espresso grinder for your business.  It is most relevant to part 3, which discusses an alternative solution to adjusting the grind size, the traditional grind ring.  But if you like what you read, why not jump back to part 1 and start from the beginning.  You might just grind the answers you are looking for!

Grind Adjustment Knob

The grind adjustment knob can be found under a number of different brands and espresso grinders produced by Nuova Simonelli.  It’s specifically the Victoria Arduino Mythos 1 that this article relates to.  Why?  Because the knob is positioned at a different angle and crucially the burrs are positioned at the same angle as the knob.

coffee grinder knob settings


To grind the coffee finer, the knob is turned clockwise, which moves the back burr closer to the front burr, via a pull rod and lever that reaches to the back of the motor.  The same system moves the back burr away from the front burr when the barista turns the knob anti-clockwise, to grind the coffee coarser.  There are numbers at the base of the knob which can be useful but do not directly refer to the size of the grind particles.

The angled burrs of the Mythos 1 allow gravity to assist with removing the ground coffee from the grind chamber.

60°Angled Burrs Diagram – Based on Victoria Arduino Mythos 1 (for simplicity the diagram does not show the adjustment knob) 

diagram of coffee bean grinder

Positives of the Grind Adjustment Knob

The knob is easy to turn – Even with the reduced leverage of a grind knob, it is easy for the barista to turn.  Firstly, the surface area of the thread is smaller than the thread of the grind ring, reducing friction and the amount of elbow grease required. As well as this the thread that pulls and releases the rod is in no way connected to the grind chamber, so does not get clogged with coffee grounds and become stiff to turn over time.  Many baristas favour the adjustment knob because adjustments are quick and easy, a real advantage when there is a queue of customers to serve.

Angled burrs reduce the need for maintenance and cleaning – When the burrs stop grinding, gravity takes over and assists with clearing the coffee from the grind chamber.  Because the grind chamber is kept clearer the grinder is less likely to block when you need it the most.  The grinder chamber will still require cleaning occasionally but not as often as with a traditional grind ring.

The grind size does not need to be re-set after cleaning the grind chamber – To gain access to the grind chamber for cleaning the thermal block, along with the front, fixed burr is removed.  When reassembled, because the burr is fixed, the grind setting will be the same as it was before cleaning.  

Remember, with a traditional grind ring it is the adjustable burr that is completely unscrewed, which means that the barista needs to spend additional time finding the desired grind size, when they could be serving customers.  But not with the Mythos 1.  When the grinder is reassembled, the barista can continue to serve coffee.

Negatives of the Grind Adjustment Knob

All coffee grinders have the potential to block – The Mythos 1 is no exception to this.  The 60° burrs reduce the chance of blockages significantly, but the throat of the grinder can occasionally block.  The blockage can be cleared by removing the thermal block and front burr, but it takes time, which can disrupt service.  This is why the accomplished barista will schedule the cleaning of the grind chamber on a regular basis, when the coffee shop is closed.  This way they can take their time and do a thorough job, without effecting service, safe in the knowledge that if their grinder jams they have done all they can to prevent it.  

Unlike the traditional grind ring, which can be removed by hand, a screwdriver is needed to disassemble the mythos 1 grinder to clean the chamber.  To remove the 4 screws that hold the thermal block in place a Philips (PH2) screw driver is needed.  Quote the code PH2 to any tools supplier and they will sell you the right screwdriver for the job! If a Pozi screwdriver or a different size Philips screwdriver is used it is highly likely to destroy the cross slot of the screws, leaving them virtually impossible to remove by anybody other than a highly skilled engineer.

Important – The grinder MUST be turned off AND unplugged from the power supply before opening the grind chamber. The exposed burrs could cause serious injury if they are accidentally turned on during the cleaning process!  Take time to explain this to your colleagues.  After unplugging the grinder, follow the cable to the grinder to make sure you have disconnected the correct electrical device.  

If your Mythos 1 grinder blocks and your baristas do not have the experience or tools required to unblock the grinder all you need to do is give us a call.  We will send an engineer straight away to fix the problem.

The throat will always be full of coffee – Although gravity assists with removing the coffee from between the burrs, some coffee will be retained in the throat of the grinder, because it is stopped by the clump crusher.  The amount, just under 2 grams, is kept to a minimum by the shallow shape of the throat.  If the barista, then uses this pre-ground coffee to test the new grind size it will falsify the result because 2 grams of the dose were ground at the previous grind size.  Therefore, once an adjustment has been made to the grind size, the retained coffee should be removed from the grinder because it was ground before the adjustment was made.  

This leads many baristas to grind and discard a double dose (known as purging the grinder) to ensure they have removed all of the pre-ground coffee.  This technique removes any uncertainty about the validity of the next extraction time, but uses a double dose of coffee every time an adjustment is made.

Grind Adjustment Knob Vs Traditional Grind Ring Summary

The grind adjustment knob and 60° angled burrs of the Mythos 1 professional espresso grinder give your baristas a real advantage when serving your customers.  Grind adjustments are easier to make with the adjustment knob and the grind chamber needs less cleaning to prevent blockages.  What’s more, as long as the barista has the correct screwdriver, and skills necessary, the grind chamber can be cleaned and blockages cleared without too much trouble or many customers being turned away.  The negatives of the adjustment knob and angled burrs create challenges that any reasonable barista will expect to face and are less so than the challenges created by a traditional grind ring.

For these reasons the grind adjustment knob and angled burrs are a great feature for high volume coffee businesses where efficiency and quality are important.  The extra cost of renting the Mythos 1 grinder is a drop in the ocean if you are selling lots of coffee and the features discussed make the whole operation run that little bit smoother.

For small to medium coffee businesses the features are also very handy.  Your baristas will have more time for other duties and will find it easier to serve good coffee.

Having said that, the traditional grind ring is a feature you will find in many successful coffee businesses.  Once your baristas have gained the necessary experience, it’s simple design brings reliability and a consistent dose of coffee.  The affordable price of our Mazzer grinders makes the traditional grind ring the most popular grind adjustment solution we offer and whilst your baristas are learning, our Full Care Rental Service has you covered!

Leave a Reply