Identifying Coffee Defects

Common coffee defects include quakers (underripe, pale, papery flavor), insect damage (small holes, musty taste), mold (black spots, dangerous), and foreign matter (stones, sticks). Specialty grade coffee allows 0-5 defects per 300g; defects are more common in lower grades. Quakers are the most common defect you'll encounter—they're underdeveloped beans that roast pale and taste like cardboard or peanut shells. Remove them before grinding by sorting visually or by density (they float in water). A few defects in a batch won't ruin coffee, but high defect counts indicate poor sorting and processing. Always remove visibly moldy beans—they can contain harmful mycotoxins.