The objective of this study is to identify, by means of the analysis of the graffiti ante cocturam on the Roman amphoras, the different processes of production which are registered in the amphorae workshops. The olive oil produced in the Baetica served massively to nourish the western provinces of Roman Empire for more than 300 years. The standardization of the selected amphoric type, which extended over more than one hundred amphora workshops, allows us to observe certain patterns of similarity in the amphoric productions, at either a typological or epigraphic level, that allow us to understand the production organization of these amphoras. We apply here a development of the categorization of graffiti ante cocturam on these olive oil amphoras (i.e. Dressel 20) that allows us to analyze the set of the epigraphs which have been published so far from a new point of view. Our work focuses on the analysis of graffiti belonging to thirteen different archaeological surveys conducted on the surface of Monte Testaccio (Rome, years 1989 to 2000 and 2005). Before now the graffiti found in the different excavations of Monte Testaccio have been studied and published independently, and only through a global analysis can we present a joint vision of graffiti for more than a century, appreciating certain patterns or key trends which are important for understanding the different processes of production of the Dressel 20 amphorae in the production areas. The results suggest that the presence of numerals responds to a clear will on the part of the artisan collective who was dedicated to the manufacture of these amphoras to quantify the lots produced in any of the various phases of a production system. The fact that one is a part of a complex system of artisanal ceramic manufacturing at industrial levels necessitated a strict organizational control of all the productive phases. The continuity over time and the dispersion of the marking method in the territory makes us think of possible well-defined standardization processes, with learning processes common to the ceramic artisan communities and their possible mobility through the different workshops that produced the same type of amphora. The same results could be understood as part of the internal control of the contracted productions, as well as constituting a log of the internal logistics of the baking phase or for its control, when storing them in one of the first phases of formation of the amphora.