Possible Clues:

• Three quarters of a second after one, sharp
• Fantastic twitch - it's to do with acid
• Vinegary puritan no saint
• It's on the cards that it's just one jerk (6)
• A single winning twitch can make one aid
• ...tart's tops in front of jerk...
• It's on the cards that there's one end to 1 across to make one acid
• -- acid (vinegar component)
• Like pickling liquid
• One such jerk is enough to make one acid