Are My Burrs Worn?

[cmotd]

I just massively upgraded my espresso machine and my grinder is my first one, and i bought it second hand from someone who didn't know how much coffee the burrs had done. So basically I'm not really sure if they are worn or not as I can't tell from the coffee I'm making or the mileage they've done Can anyone out there tell from this picture if they are worn and need replacing?

[blend52]

No, it's not possible to tell from a photo.
its probably worth the cost of a new burr set to know for sure if you seriously suspect they are past their best.
...just consider it part of the cost of your "massive upgrade" !

[MorganGT]

In my experience it's hard to tell if burrs are worn from looks alone, and I probably assess various burrs for wear half a dozen times a day! They don't look too bad from the pics, worn but usable - signs of damage or excessive wear are dings or nicks along the edges of the teeth, or a wide shiny edge to the teeth where the sharp cutting edge has been worn down to a chamfered edge rather than a sharp point.

My golden rule is to rub the upper surface of your thumbnail across the surface of the burr against the rotational direction of the burr - dull but usable blades will leave scratch marks on your nail, sharp ones will scratch your nail deep enough to leave nail shavings behind (best to wipe these off before reassembly unless you want coffee that tastes of fingernails!)

Also note that on a lot of grinders the upper and lower burrs don't generally wear at the same rate, so check both, and if the most worn burr seems too worn, change them.

[Mariner]

Hi cmotd, great question. I have wondered this too. But, from my perspective, especially as I am a home user, I have always thought that as long as my coffee tastes great and I have no trouble dialling the grinder in then they are not too blunt. Like any other similar piece of rotating machinery like this, I guess there would be different levels of satisfactory. A commercial venue may require a fast and efficient machine working to the best of its ability to satisfy a high demand. I've got to stop using comparisons..... but a hairdresser uses their blades a lot, so must sharpen and replace a lot to meet the demands of their commercial use, where I just have to run a number 2 clipper over my head every 6 weeks with my own equipment the gear works fine and the result is great but I doubt the gear would be in good enough working order to serve a working business.

[cmotd]

Thanks for your replies, I guess I'll go home and shave my fingernails!