What is a Coffee Destoner?

What is a Coffee Destoner?

First of all, what is a destoner?

A destoner is a machine we run the beans through after roasting to find any potential foreign matter that may have shipped to us with the green coffee. This could be small stones, chips of concrete, small pieces of the coffee plant, twigs, etc. The machine is very simple in how it works – a roasted coffee bean is very light, lighter than small pebbles and pieces of wood, so vacuum air is pulled across the roasted coffee with just enough force to lift and carry away roasted coffee beans and leave behind everything else. This can also include coffee beans that didn’t roast properly because they were under-ripe, these beans are known as Quakers to the coffee roaster. 

While finding a Quaker in the destoner makes sense, what about finding a stone? How does that get there!? The answer to this is found in how coffee is processed around the world. Most countries that grow coffee still use a very low-tech, yet tried-and-tested, way to process and dry coffee beans. This often includes spreading the washed and process beans across either screens, boards, or concrete to let them naturally dry out. While this is a very eco-friendly way to dry beans, when the dried beans are gathered back up, other material may be gathered with them.

Destoning in an important part of the roasting process. Removing underripe beans will give you a cleaner taste to your coffee, and no one wants the stones to destroy their coffee grinders' burrs.