As a small roaster we can not justify the expense of a de-stoner, nor do we do the volume to justify it. However, as our coffees find their way into more and more cafes I become exceedingly worried that the stones I frequently find loading the batches will make it into a nice grinder and I'll be buying someone new burrs. Anyone have an economical, sure-fire method to keep stones out of my final product? The current system is a careful eye at every step of the roasting process. There must be something out there as I know of roasters who crank out 1500 pounds a week and they do not have a de-stoner.
Thanks in advance for any and all help.
Colombia sometimes exports gravel with coffee and Nicaragua seems to like to include metal trinkets. But like everyone else has said, Sumatra is definitely the origin of a lot of rock. In one *triple pick* bag I've found candy wrappers and cigarette butts, along with some sort of plastic idol that thankfully was spotted before heading into the hopper.
If you are in a warehouse environment, building a destoner is pretty simple. You'll just need a blower and a friend who can weld. But if you are in a cafe environment it can get a little tricky balancing aesthetic & noise... I find most roasters spot these things in the tray or before loading while scooping.