“They turn red litmus paper blue” crossword clue

Reveal the answer to see why it works and where this clue has appeared before.BASES is the answer to the New York Times crossword clue “They turn red litmus paper blue”. It was last seen in the puzzle of December 14, 2025, where it runs at 41 Across and fills 5 squares. It crosses 5 other entries in that grid — those are listed below and are the quickest way to confirm the letters you already have.