Post By DesigningByCoffee
Breville Grinder - Broken by Rock?!
Aw man I'm pretty annoyed, my grinder seems to have been bunged up by a rock hidden in the coffee beans that I buy.
The grinder seemed to free spin all of a sudden, which is when I noticed the rock wedged in the burrs. After removing the rock and testing, the grinder does seem to spin but now with a 'clunking' sound at a rate of about 3 clunks per second.
Anyone have a gut feeling on whether this is something that I can fix, or is it more likely some vital components have been irreversibly damaged? Maybe they are built to disengage in such an event?
Any tips would be great as I'm out of a grinder and don't have a budget for this right now.
FYI it's just the cheapo Breville BCG400 that comes with the BEP810S pack.
Last edited by ajm07; 22nd February 2017 at 09:54 AM.
Reason: Adding Image
Did you remove the burr as there may be another piece of rock further in. Other than that I don't know anything about a Breville grinders. I have had the odd rock go through my grinder but they didn't slow it down, must have been a solid piece.
Just for interest sakes - whats the background to the beans with the rock in it?
Were these Green Beans you sourced / roasted yourself?
OR Roasted Beans, bagged n ready for use?
I can't say I'm that surprised that a very low end grinder would be trashed by a small stone.. I guess you gets what you pays for...
I once saw a blog post on the topic:
The topic of stones in coffee is somewhat of a taboo amongst coffee roasters. Most are not prepared to comment.
Some smaller coffee roasting operations don't run a destoner and they just hope that no stones find their way into the final product. They might justify their inaction with statements like "I only buy good grade beans" or "I do a visual check", but anyone who has run a destoner knows that you find all sorts of objects in all sorts of grades of green coffee. Merely looking and hoping doesn't always work!
If you are purchasing coffee, it's not a bad idea to ask your roaster how they handle stones. You may well have some homework.
So what do you do?
We run a small destoner and every roast we do passes through it. I have seen and heard of destoners finding items such as:
- rocks and concrete
- mud that looks like stones
- bullets and coins
- drop earrings
- engagement rings
- sticks and twigs
- nuts, bolts, screws and nails
- lentils and maize
What do you find?
In most of our roasts, we find nothing. In perhaps 1 in 5 batches, perhaps 1 or 2 small concrete stones. If these were to find their way into a good quality grinder, they might sound a little scary, but will ultimately do no damage. Grinder burrs are much harder. In perhaps 1 in 100 roasts, we might find something nastier. We love seeing coffee flavoured popcorn in the cooling tray as it provides a yummy snack!
So destoning is the panacea then?
Coffee destoning should remove most rocks and hard objects if the destoner is correctly tuned and adjusted for that batch of beans- but they are not infallible. The only way of guaranteeing you won't find something other than coffee is to do a visual check before you load the hopper of your grinder.
At xxxxx, we use a large perforated cooling tray which allows smaller stones to fall through after roasting. We then destone the output to seperate larger stones and other dense objects. Anything with a density lower than a roasted coffee bean can still get through (for example a small twig), but would be sterile (roasted to over 200C) and the grinder would likely not notice it. On rare occasions and even with the best of processes, stones can find their way into your bag of beans regardless of where you purchase your coffee. It sometimes happens.
At least, I know we have done our utmost to avoid stones... Some may say that forewarned is forearmed!
I have found a few mostly conglomerate that the grinder has no trouble with. I buy green beans and roast myself. I have detected stones in green beans several times as I cool my beans I check what is in the sieve. I also watch as I pour then back into a container prior to bagging and I have found them mostly in the bottom of the seine. As coffee is a natural product they can be contaminated in processes such as drying etc. it is always a good idea to be aware they can be there and keep an eye out for them. If you put the beans in a seize and give it a good shake the stones normally go to the bottom and can be removed.
There is also a plan for building a cheap de-stoner somewhere in the forum
The stone has jammed the burrs and the motor will have kept trying to spin. This grinder has no torque limiter or slipper mechanism to speak of so the metal motor gear chews away the nylon drive gear. The clicking noise you are hearing is the motor hitting the flat spot on the drive gear.
Some of the Breville grinders survive a stone or other debris but others don't. I think there is some sort of safety mechanism in the gears which kicks in if the grind gets too fine or jams up and slows the motor but a sudden stop like a stone it can't deal with.
There is no source for this gear except as a salvage part from a BES860 or BES870 machine or a Smart Grinder that has broken down in some other way.
A home made Coffee De-Stoner.
I can't work out how to put the link in but if you search de-stoner it will give you several previous post that show how to make one. Apparently I did get the link right
You'd be a bit dark though if it was in commercial beans - the OP says they were bought. Seeing how many stones I've picked out with my DIY destoner home roasting, I'd shudder to think of a commercial operation not using one!
This was jammed in pretty good - the jam also prevented me from unscrewing the burrs making it difficult to remove. Took me a good 5 minutes to pry it out.
The beans were roasted, bought online in 500g pack through ozbargain. I've been offered some cash to replace the grinder so that's good I guess, though as I can't find this grinder for sale anywhere I'll probably need to replace it with the BCG600 and still be out of pocket by $80. I'm happy they were willing to pay up something, but still feel a bit jipped. (Is it my right to have rock-free beans? - or is it a hazard that I accept as a coffee drinker?). I guess I'll just take what I'm given.
While not much can ever be truly guaranteed, buying beans from a reputable local roaster or, if online, somewhere reputable like Beanbay or one of the sponsors below will give you far greater peace of mind, even if you need to pay a little more. As you've just found out - cheap coffee is not always cheaper in the long run!
Originally Posted by ajm07
Just wait till the grinders on your bench get more expensive as snobbery takes hold
Im surpised they even offered you that. Ive only even had one stone through my grinder and my supplier is pretty careful.
No damage done fortunately