Categorizing of Finish Good based on production quality

Hi SAP Gurus

We are producing SOLAR Panel , but we are categorizing our Finished Goods based on production quality , say A, B , C , D.

A if get get best quality that will be decided by QM and similarly rest of categories are defined.

On commencement of production order we can not knowing what quality we will be getting , it is only defined after realizing the end of the production.

How we can best do this in SAP by MM or QM  . So that we can identify that which solar panel belongs to which category.

Thanks

Regards

Gaurav Solanki