The number of grams in a US fluid ounce will depend on the substance:
There are 31.35 grams in a fluid ounce of evaporated milk;
30.46 grams in a fluid ounce of fresh milk;
29.574 grams in an fl oz of water;
17.744 grams in an fl oz of wheat flour; and
A sugar fl oz converted to grams equals 25 grams;
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