Acide vs. aigre
In French, the words 'acide' and 'aigre' both relate to taste sensations but are used in different contexts to describe the nuanced flavors that fall within the range of sourness.
Acide
This term is primarily related to chemistry and often refers to a sharp, pungent taste typically associated with acidic substances.
Ce vin a un goût acide.
(This wine has an acidic taste.)
Les citrons sont naturellement acides.
(Lemons are naturally acidic.)
Un excès de café peut rendre l’estomac plus acide.
(Excessive coffee can make the stomach more acidic.)
Aigre
'Aigre' is generally used to describe foods that have a tart or sour flavor, often resulting from fermentation or spoilage.
Le lait est devenu aigre.
(The milk has gone sour.)
J'aime le goût aigre des cornichons.
(I like the sour taste of pickles.)
Cette crème fraîche a une saveur légèrement aigre.
(This sour cream has a slightly sour flavor.)
Summary
'Acide' and 'aigre' are both French adjectives used to describe sourness, but 'acide' often relates to the sharpness of acidity, as in citrus fruits or vinegar, while 'aigre' commonly describes the result of fermentation or the tartness of spoiled food. The choice between them depends on the context of what is being described.