Breville BCG450 burr grinder modification instructions

So I picked up a new Breville Coffee Grinder on the back of reading a lot of reviews on, saying that with a “simple mod” to the machine, you can get it to perform like a grinder 5X it’s cost. Sounds good right? Well, sure, except it was actually really hard to find the actual instructions for modifying the grinder in the first place! So, here they are in all their glory:

How to make the Breville BCG450 burr grinder grind finer! Guide

Thought I should let all you guys out there who desire to revoke their
guarantee in favor of getting a finer grind out of this machine know
how it’s done. Well, you’ll be happy to know that, IT’S REALLY
EASY! šŸ™‚
I’ll scare you a bit in the disclaimer, but it’s really a simple task
for the non-incompetent.

I’ve got a Gaggia Classic and originally this grinder was far from
grinding fine enough. After this mod I am very happy with it,
considering I will hopefully not have to get another grinder. I’m
still tamping as hard as i can, but before i was getting 7 second
shots, now after the mod i’m getting 20-25 seconds. Sometimes there’s
still some to be desired from the grind, but it’s a different world to
what i had before.

This “guide” is for the Conical Burrs set. I’ve seen on the net
pictures of older FLAT Breville Burrs, if you have these, this guide
This guide is for a machine that has the same burrs as a Solis 166,
but this solution is different because there is no individual holes-
ring for calibrating the grind. On the Breville, this ring is
incorperated into the plastic housing that sits over the bottom burr
and houses the top burr in it when you put it in.

This is not a GUIDE per se. The reader takes all responsibility for
his actions taken as a reaction to this post. This is friendly advise
to those who are interested. If you are interested in taking the
dangerous actions advised in this post, it is your sole responsibility
and fault at that.
Read the instructions well and make sure you understand them. I have
tried to explain how the machine works so that you can figure what
modification you must do by yourself.
If you are incompetent with basic screwdriver use etc. please don’t
follow these steps, you might do damage to the machine and to
yourself. If you are competent, you still might do damage to the
machine or to yourself. Beware.
This modification will allow you to get the burrs as close as touching
– and then some. Be aware that turning on the machine when burrs are
touching is most probably very bad for it. At the least – never turn
it on with burrs touching and with no coffee beans in the hopper. The
coffee will keep the burrs from destroying each other.
If you are intending to follow my advice, please read the whole thing
before you start working.
Remember, by following these steps you are most definitely revoking
your guarantee.

1. Safety first, unplug machine from electricity! šŸ™‚ Take out bean
hopper and top burr and set aside.

2. pull out the 4 rubber legs and Unscrew all screws (7) from bottom
of grinder. These are triangular-hole screws, but they can easily be
screwed out with a small flat screwdriver. Take bottom cover off
grinder. Two parts here.

3. Unscrew 3 more philips screws from the bottom of the grinder,
you’ll need a relatively long screwdriver to get to these.

4. Pull out button and knob on the front of the machine. They come

5. carefully pull the body cover off, being careful to lift it over
what’s left of the knob, and taking care not to lose the loose plastic
piece that sits under the button (keep it in a safe place with the

6. Now that the cover is off – OBSERVE the turning section above the
grinder. (see NOTE at end of post) turn it all the way clockwise
(looking from the top). This is your finest grinding setting. Now
observe what is stopping the ring from going further clockwise. You
will see a little nub on the ring turning until it hits a plastic
chamfered ridge on the body. You can also see that a little further
clockwise there is another ridge – this time straight and lower. This
second ridge is just like the ridge on the other side that keeps the
ring from going too far counter-clockwise.
Now you have observed how this works, and that the chamfered ridge is
an unnecessary (to us) restriction to the intended operationg range of
the grinder.

7. Carefully cut the chamfered ridge right off. If this is hard to do
with the ring/cover on – it can be taken off. instructions for taking
off ring: Make sure ring is turned all the way counter-clockwise. then
carefully pull it off. I’ve done this many times and nothing broke. Do
it with your own responsibility.

8. Now observing again: Turn ring all the way counter-clockwise and
put the top burr in. Turn ring all
the way clockwise and observe that now that the chamfered ridge is
gone, you can turn the ring all the way to the second ridge. When all
the way clockwise – observe how the top burr sits snuggly in it’s
intended place – as far down as it was engineered to be able to –
without the restriction.

9. turn ring all the way counter-clockwise. (take top burr out if you
put it in)

10. Put cover back on the machine while making sure that the little
plastic piece from behind the button that you kept safely, is back in
it’s place.

11. Put knob and button back in their place – making sure they are
fitted correctly.

12. Screw in 3 philips screws, then 2 plastic covers and 7 triangular
screws on the bottom of the grinder. put back 4 rubber feet.

13. Put top burr in it’s place, put bean hopper in it’s place. Observe
before connecting to electricity – how far your bean hopper turns past
the “very fine (turkish)” setting. Should be about an inch and a half
further than the end of the marked settings.

Have fun and good luck!
Feel free to email me with any questions.

(from stage 6)
(on the bottom side of this cover/ring you will see a circle of holes,
this is the equivalent of the Solis hole-ring, but it doesn’t come
apart, does it… Well, thanfully, we’re doing something else.
You will also be able to see, that if you put the top grinder stone in
and turn the wheel all the way clockwise, it will still rock in place
and give an uneven grind, because it is not as far in it’s grooves as
can be! They dont let you go as far as they know you can so you dont
ruin the burrs and blame them! Good thinking, Breville!
But that’s just what we’re doing, taking off their restriction and get
to what this machine was actually engineered to do. they just added a
plastic restriction so it can’t get as far as intended.

Have a nice day,

I’ll update everyone on how I make out with the modification later.


5 thoughts on “Breville BCG450 burr grinder modification instructions

  1. Better late than never. U still have that breville conical grinder working. Iā€™m thinking of doing it to mine

  2. Hi,

    I have mod on my Breville grinder (done the removal of stopper to allow finer grind), but while removing the top burr I found out there was a lot of play between the part and the inside plastic ring for vertical alignment. After removing the gump on the burr, I added a single layer of masking tape so the part would be slide fit with some friction. The end result: I can now get much finer grind than before at the same setting!. And if I go past the original stepper, the burr are too close and have some intermittent contact.

  3. Excellent instruction set mate…..much appreciated….I completed the mods and am awaiting time to test for the grind results…..I managed to get 4 extra fine grind settings before the burrs start to contact.

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