The antonyms of "acetify" are words that indicate the opposite of acidifying or turning sour. Some of these words include alkalize, neutralize, sweeten, or de-acidify. Alkalize means to make something less acidic and more alkaline or basic. Neutralize refers to the act of canceling or balancing out the acidity of a substance with a neutral one. Sweeten means to add sugar or another sweet substance to something to make it less sour. Finally, de-acidify means to remove or reduce the amount of acid in a substance. All these words represent the opposite of the process of acetification.