The drying takes place already during the Sulfurization phase and it can last several days, because it occurs in a humid environment. Only in the final phase does the drying of the strings take place with exposure to the sun.
Only in recent times have I managed to reproduce the ancient practice of rewinding, that is, twisting the strings as they dry in the sulfurization stove. This allows the guts to remain in contact throughout the drying phase, so that the sulfur bridges multiply without breaking.
In fact, if drying is carried out in an uncontrolled environment and without twisting the strings at the right time, the individual guts, drying out, separate and break the chemical bonds that had formed up to that moment with the consequence that the string is not very cohesive and therefore fragile and not very elastic and sonorous.
At present I think I am the only one who has a "smart" machine, invented by me, which operates controlled drying, rewinding and sulfurization at the same time.
This process allows to create beautiful translucent and golden, flexible and sonorous strings, as Francesco Galeazzi (Elementi teorico-pratici di musica) describes the ideal string in his treatise.