When the time is right, Grana Padano cheese is checked with traditional tools – a "martelletto" (hammer), an "ago" (needle), and a "sonda" (plugger). If a more thorough check is needed, the cheese is split.
This small, finely-balanced steel hammer is an irreplaceable tool for checking the cheese, a process which only a select few can carry out. Tapping the surface reveals any irregular holes, called “occhiature” within the cheese, or any cracks in the structure, which are caused by improper fermentation.

This long, coiled needle is inserted into the cheese in order to check its aroma and flavour.
These simple, traditional checks do not damage the product in any way; however, if an expert wants to be completely sure of the cheese’s quality, a plugger is used to take a small sample, about half a centimetre in diameter and 7 - 8 cm in length.
This test reveals the colour, scent and elasticity of the cheese and discovers any faults, such as irregular holes or splitting.