There are many different coffee grinders to choose from when starting your coffee business.  This article is just 1 part of a series of blogs designed to help you choose the best coffee grinder for espresso.  So, if you find it useful, I would recommend you start at blog number 1 in the series for even more useful information.

Function – Clump Crusher & Static Control.  Nuova Simonelli Vs Mazzer

For this part it makes sense to combine the clump crusher devices with the anti-static devices.  This is because the Mythos 1 clump crusher also acts as a rather efficient anti-static device.  In addition to this the anti-static device fitted to the Mazzer grinders has an impact on clumping.

Clumping Explained

Clumping happens when clumps of coffee grinds form in the dose produced by the grinder.  This is most likely to happen when the grind size is very fine.  Other factors that will increase the likelihood of clumping are a humid environment and constant use of the grinder which creates excessive heat.  Essentially clumping results in an inconsistent density of coffee grinds within the dose, the clumped grinds being denser than the non-clumped grinds.

For a well-balanced espresso it is important that the coffee in the portafilter is as evenly distributed as possible, so that the water flows through the puck of coffee as evenly as possible.  This is because, when the water is pumped through, it will take the route of least resistance, over-extracting the less dense areas and under extracting the denser areas.  This problem is known as “channelling”.

coffee channeling and clumping diogram

It is the job of the barista to reduce channelling as much as possible by using good distribution technique before they use the tamper.  If the dose is tamped straight from piling up in the basket, it will be denser in the middle (where the pile was higher) and less dense around the outsides.  Good technique will level out the pile of grounds and improve the distribution of grounds.  To do this the barista will usually use the side or cup of their hand to tap the portafilter, this levels out the coffee in the basket and shuffles all of the grounds into a more homogenous dose ready for tamping.

leveling out portafilter example

Levelling out the pile reduces channelling.  It may also reduce the gaps between the clumps and grinds, but the clumps will remain largely intact.

Static Explained

When the burrs turn inside the grinder, they do a great job of crushing the coffee beans into tiny particles for brewing.  But a by-product of this is friction.  Friction causes heat, but it can also cause an imbalance between the negative and positive charges within the grinder and grounds themselves.

Subsequently, when the grounds exit the grinder, they will spray out, as they are attracted to anything that is made of metal.  Like the grinder itself!  This causes a huge mess and because the grinds fly everywhere, the dose is dramatically reduced.

Static is more likely to cause your baristas a problem if they are using a cheap coffee grinder that is constructed from plastic.  The grinders we supply are made from metal, and so this will dramatically reduce the chances of this annoying problem occurring.  However, even with a good quality, metal grinder, other factors can cause the same problem.  These include the coffee and environmental factors such as low humidity levels.  Because the static builds up as a result of friction, the faster your burrs turn and the harder you work your grinder the more likely you will end up in a mess.

static build up example coffee grinds


Mazzer Static Screen

The Mazzer static screen can be found on all of our Mazzer Electronic and Automatic espresso grinders.  The coffee grinds are pushed through this clever little device as they exit the throat of the grinder.


Positives of a Mazzer Static Screen

Its effective – In almost all cases the static screen eliminates the imbalance of charges within the grinder before the grounds exit the throat.  What’s more, because the device is fitted to our Mazzer grinders as standard, most commonly, the static problem never occurs in the first place.

Durability – The grid is made from durable stainless steel.  It is rare that our engineers would need to replace the static screen because it is damaged.

Negatives of a Mazzer Static Screen

It doesn’t always work effectively – In some environments the Mazzer static screen is in-effective.  This is rare and we have found that any type of investigation to understand exactly why the problem is present, is usually futile.  Therefore, when this happens it is likely that we would suggest a different grinder.  I can’t think of an occasion where a simple swap of grinder hasn’t solved the problem.  Our Full Care Rental Service includes grinder and espresso machine changes, so there is no extra charge, and our customers have not wasted their hard earnt funds on a coffee grinder that is unsuitable.  We simply switch the grinder and adjust the monthly rental charge.

It causes clumping?? Maybe not! – A common misconception is that the static screen causes clumping.  But this is not true.  Instead of clumping, the grid of the static screen acts like cheese wire, cutting the coffee grinds into bricks as they pass through the screen.  Remember clumping is caused by a very fine grind and will happen without the screen in place.  So as the blocks from the static screen are caused by a different factor to the clumps, they are different.  But the more crucial question is, are they the same density?  Afterall it is the density of the clumps that causes the channelling.

This is admittedly something I have no proof for, but it seems likely that the bricks are not as dense as the clumps.  After all the clumps form naturally, but the bricks are cut from non-clumped coffee grinds.  Of course, the grinds that pass through the static screen can be clumped already in which case you will have a clumped and bricked dose, but the 2 are separate.

If the bricks that are produced by the screen are less dense than clumps the channelling it causes is reduced and the customer can enjoy a well-balanced espresso.  Afterall, Mazzer grinders are used by Speciality coffee shops and coffee roasters to produce great tasting coffee every day.


Mythos 1 Clump Crusher

The Mythos 1 clump crusher is a fantastically simple but effective piece of design.  It sits within the throat of the grinder and is made out of thin plastic, which helps it to vibrate as the coffee grounds pass through.

mythos one clump crusher examples

Positives of the Mythos 1 Clump Crusher

It’s effective at removing clumps As the coffee grounds passes through the nylon fingers it causes them to vibrate, which in turn does a great job of removing the clumps.  Producing a consistently fluffy dose of coffee grounds perfect for good distribution and a balanced espresso.

It’s effective as an anti-static device – The clump crusher also eliminates any static build up in the particles before they leave the throat of the grinder.

It produces a consistent flow of grinds – The consistency of the vibrations and the resistance of the fingers against the coffee grounds exiting the throat, means that the grounds flow into the basket at a steady rate.  This is a big advantage for on-demand grinders as they produce the dose of coffee based on time.  The result is a more consistent dose weight and balanced espresso for your customers.

Negatives of the Mythos 1 Clump Crusher

Durability – Because the clump crusher is made from thin plastic, it is not durable.  If the throat blocks with coffee grounds, it is likely an inexperienced barista will stick something up the throat to try to unblock it, damaging the clump crusher in the process.  If the clump crusher is not damaged by user error, it will last a good number of months before the fingers start to bend out of shape.  As this happens, clumping will start to appear.  A sign the clump crusher needs to be replaced!

The screws – Replacing the clump crusher on the Mythos one grinder is simple in theory.  But if the wrong screwdriver is used, it is very easy to damage the screw.  It will become rounded off and then even more difficult to replace.  Our Full Care Service includes all maintenance, so if our customers suspect the clump crusher needs to be replaced, we will send an engineer to complete this pitfall ridden task with no hassle whatsoever.

Clump Crusher & Static Control Device Summary

Both Mazzer and Nuova Simonelli (the manufacturer of the Mythos 1 grinder) have a great solution to the problem of static build up.  However, where clumping and dose accuracy are also a priority, the Mythos 1 grinder wins.

So, who should be concerned with clumping and dose accuracy, and who should not worry about it so much.  Well, if you are using speciality coffee, and you are using a premium La Marzocco or other multi boiler espresso machine it is worth renting the Mythos 1 grinder to do them justice.

But the most important factor to look for in a grinder is the on-demand function which produces freshly ground coffee.  For this, the Mazzer on-demand coffee grinders are a good option and are used to serve speciality coffee in many successful coffee shops.  Depending on your coffee and how often you use the grinder the Mazzer grinder may or may not cause clumping.  So, if you want to serve great coffee but don’t want to spend more of your cash than necessary it is a good idea to try the Mazzer on-demand grinder.  This way you can see if clumping occurs with your coffee.  If it does and you wish to eliminate the problem along with a more consistent dose.  You can always upgrade to the Mythos 1 grinder later.

For those who are not so concerned with the taste of their coffee because maybe their customers mix it with milk and syrup, the Mythos 1 clump crusher is not necessary, and less is to be gained by renting this fantastic but more expensive grinder.

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