the sourness of milk
a sense of sourness
bitter sourness
A: How do you like the fresh lemonade?
A：你觉得这杯新鲜柠檬水怎么样？
B: The sourness is quite refreshing, but it could use a little more sugar.
B：酸味非常清爽，但可以再多加点糖。
1) 指食物或味道的酸度
2) 指情绪上的不满或愤懑
3) 指性格中的刻薄
1. 酸味；酸度
noun
1. The quality or state of being sour in taste.
2. The quality of being bitter, resentful, or unpleasant in manner.
Synonym: acidity, bitterness