Expert: Chanda Walker - 4/22/2009

Question
I need 72% water and 28% of dry flakes.  One friend told me to take 1 pound of the flakes and that I would need 23 ounces of water and I would have a 72% to 28% mixture.  When I got to the post office to use their scale, the mail clerk said that I had to measure out 16.70 of weight to equal the 1 pound of dry flakes.  That I did.  One pound of flakes and 23oz were supposed to make 40 oz and fill up 10 (4 oz) bottles but I was short 14 oz. What did I do wrong?

Answer
The difference probably is in the fact that ounces by weight are not the same as ounces by volume.  Your bottles are measuring liquid ounces.  Your scales are measuring weight ounces and they are NOT the same thing.

You can try to prove it to yourself.  Take that pound of flakes and try to fit it into a 2cup measuring cup.  My bet is that it doesn't fit.  I bet it is very much larger.  However, when wet that stuff will shrink down to no size hardly at all which is why your bottles are under-filled.

If the dry flakes are food, you should measure them not by weight but by volume.

However, that isn't the most basic of your problems.  If you are using 16.7 ounces of flakes and only 23 ounces of water, you are not using enough water for your flakes.

For 2cups of flakes (which is 16 ounces) you'll need:

16/x = 28/72

x = (72/28)*16

x = 41 ounces of water.  That is roughly 5 cups of water.

If you want to do it by weight instead of volume, though it doesn't sound like the right way to go to me,

For one pound of flakes you need 2.6 pounds of water.