What is Spot Size?

Spot size is best understood as a circular area that the Pearl Mini uses to assess colour. The machine does not measure the bean itself but focuses on whether a coloured (quaker) portion reaches or exceeds this set spot size.

While spot size is used on Patio, Quaker & Burnt, this article will mainly talk about quakers, however the same principles still apply to Patio and Burnt.

• Spot size does not correlate directly with bean size, although smaller beans can affect how colours appear relative to the set spot size.

• A spot size of 100 is approximately equal to the surface area of an average coffee bean, however the coffee bean you'll be sorting may be bigger, or smaller than this.

When you run the Pearl Mini and start sorting, the cameras will first look at the bean to see if it matches the colour of the Quaker Acceptance Range, and then it will check if the size of the colour meets or exceeds the Spot Size.

Keep in mind if you are sorting a smaller than average coffee bean (Peaberry for example) you may need to lower your spot size by 2-5 points. However this should only be done after you've lowered your Acceptance Range.

We recommend starting with a spot size of 45 for quaker. This means roughly, half or more of the bean needs to be quaker coloured for it to be rejected. If your machine isn't rejecting obvious quakers, and you've adjusted your sensitivity settings then you may want to consider reducing your spot size.