I don't understand what this term means:

Question

"Vinegar must not be less than 4% by mass acetic acid."

Answer 1

I don't know where you found this quote but it means that vinegar, sold to the customer, must contain at leat 4 grams of acetic acid for each 96 grams of water. Does that help? I don't know if that is a FDA regulation or not.

Answer 2

thank you, i found this in my lab book.

Answer 3

I looked it up on an FDA site and found that vinegar MUST contain AT LEAST (it may contain more) 4% acid