Is Varista the correct term? Or are we, again, bastartizing language, so to speak. Here is an opinion from Counter Culture Coffee:

In Italian, most masculine words ending in ‘o’ are pluralized ‘i’. Like un gatto, due gatti (one cat, two cats). Feminine words ending in ‘a’ are usually pluralized ‘e’. Un pizza, due pizze.

“Barista” is irregular. Since it is the Italianized version of the English word “Bartender”, it is considered a foreign word. All foreign words are considered masculine, and therefore pluralized with the “i”. un barista, due baristi. Strange how it works, English word becomes Italian, Italianized word becomes English again.

We sometimes use the pluralized version of Italian words. Papparazzi, for example. Pepperoncini. Biscotti. Other times, we use English pluralizations. Pizzas, gelatos.

I, myself, use ‘Baristas’ and ‘Baristi’ interchangeably.

Link via t o n x . o r g and Counter Culture Coffee