The black core is a localized area marked by a brown/black (or even white) color, clearly visible in the thickness of the ceramic tile. Its presence is usually sign of inadequate oxidation and it has not to be considered as a defect that compromises the product functionality. However it's a very serious aesthetic problem, especially if we consider the increasingly different intended use of ceramics. The origins of this particular defect are many and, according to the specific production conditions, even the actions and solutions to reduce or prevent it can be different. The episode focuses exactly on this topic, offering a journey that starts at the origins of the problem,and then ending with a range of possible interventions.