Learn Portuguese (Portugal): A rolha não deixou sabor nenhum no vinho. - The cork did not leave any flavor at all in the wine.

Placing nenhum after the noun (sabor nenhum) adds strong emphasis to the negation, translating to 'no flavor at all' or 'whatsoever'. If it were placed before the noun (nenhum sabor), it would be a standard, less emphatic negation meaning simply 'no flavor'.

Could I use qualquer in this sentence to give the same emphatic meaning?

Yes, but its position changes. To get the same emphatic 'at all' meaning using qualquer, it must go before the noun: não deixou qualquer sabor. Both sabor nenhum and qualquer sabor are excellent, interchangeable ways to emphasize a negative.

Is não deixou sabor nenhum considered a double negative?

Yes! In Portuguese, double negatives are grammatically correct and required. Because the negative word nenhum appears after the verb, you must have a negative word like não before the verb to make the sentence grammatically complete.

Does rolha mean any type of bottle cap?

No, rolha specifically means a cork. If you were talking about a metal bottle cap (like on a beer bottle), you would use carica, and for a general plastic lid or cap, you would say tampa.