Feature of Granny Smith apples

• Feature of Granny Smiths
• Sourball quality
• A sharp sour taste
• Crab apple's quality
• Vinegary quality
• The taste experience when vinegar or lemon juice is taken into the mouth
• Pungency

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Tartness \Tart"ness\, n. The quality or state of being tart. Syn: Acrimony; sourness; keenness; poignancy; severity; asperity; acerbity; harshness. See Acrimony .

Wiktionary Word definitions in Wiktionary
n. The characteristic of being tart; sharpness of taste; sourness; bitterness.