"I cuochi bevono le birre."

Translation: The cooks drink the beers.

[strages]

cuoco -> cuoc. last letter is a "c" so always an H will be added in case of a male plural?

[f.formica]

Not always, but most often: usually the plural preserves the sound of the letter instead of its written form so a "k" sounding "c" becomes "ch", and the same happens for "g" to "gh". For "ch" sounding "c" and "j" sounding "g" the change often happens in the accompanying vowel, for instance "il bacio" to "i baci".

[Pablo-Enzo]

Cuoco sounds like 'cuoko', if the plural was Cuoci it would sound like 'Cuochi', so to get the k sound back and make it sound like 'cuoki' it's Cuochi instead.

This happens with most of the words that have consonants on the last syllable which change depending on which vowel is after it.

[jaybeebee]

In English you would very rarely say the "beers". Beer is neither singular nor plural. It is just beer !