Which factor can lead to the classification of rum as 'artisanal'?

The classification of rum as 'artisanal' is primarily associated with small scale production. Artisanal spirits are typically crafted in small batches, which allows for a greater degree of control over the production process. This often leads to unique flavors and characteristics that reflect traditional methods and local influences.

Artisanal producers may prioritize quality over quantity, using natural ingredients and emphasizing traditional techniques that have been handed down through generations. This contrasts sharply with large-scale production methods, which often prioritize efficiency and consistency at the expense of unique flavor profiles.

The other factors listed do not align with the principles of artisanal production. Mass production focuses on creating large quantities of a product, which is contrary to the ethos of artisanal crafting. The use of artificial flavors is more associated with industrial production methods rather than traditional artisanal practices. Lastly, while high alcohol content can be a characteristic of certain rums, it does not necessarily indicate an artisanal approach to production. Therefore, small scale production is the defining factor that leads to the classification of rum as 'artisanal.'