Let's talk Cup Size

(Tom Seest) #1

Yes, I know the title sounds awful, but I wanted all you food experts too actually read the post. So, I’m guilty of the “tease”. My apologies.

I’m confused by the term fluid ounces. I’m not expert in the subject but it would seem powder, liquid, air, etc. would all be measured as the same. So, when I see recipes that say “fluid ounces”, etc.; I find them confusing.

I would appreciate some clarification.


Very cheeky title indeed…:laughing:

It’s just a term to describe a unit of measure, as a volume. Doesn’t mean it has only to do with measuring liquids. One fluid ounce is approx 28 (UK) or 30 (US) mL, depending if you mean UK fluid ounce or US fluid ounce.

So, it doesn’t matter if you measure a powder or liquid…a fluid ounce is a fluid ounce. Just make sure you know which one they mean…UK or US version (or just live with the few mL of discrepancy).

Also, when baking, it is better to use weights for dry ingredients, as opposed to volumetric measures. That’s because powders can expand or pack down into the measuring container. If you put a powder in a container, and tap the side, you will notice the powder level will lower. Typically, if a recipe uses volumetric measures for powders, don’t tap the container. Take a flat edge, like a knife, shave off the top to make the dry ingredient flat at the top, and that’s it. If you want more precise measure, find a recipe that uses weights of dry ingredients instead.

Hope this helps.

(jim schafer) #3

an 8 oz cup is pretty standard (here in the usa)…a few recipes ask for things by weight…but that just drives me nuts…i know some things shrink or expand with temperature…so a fluid oz might make a difference…do you ever hear the term solid oz ?

Most of the time i consult a half dozen recipes of what i plan to make and just “wing it”…I’m not that exact in the kitchen… but this method keeps it interesting and FUN.

(kimhowerton) #4

I recently experienced this issue with my non-keto new to cooking dad.
He read a recipe where they listed:

1 cup honey /12 oz
1 cup vinegar/ 8 oz

I watched him measure it out and was like “WHOA THERE! that’s too much honey!” Because he was using the oz in that as FLUID oz.
There was a hint - the cups vs oz not being the same.

Yes, I know honey isn’t keto but I use to show the diff- that a heavier substance will have more weight per cup than a lighter substance.

A liquid that is close to water (like vinegar) there won’t be a huge difference btwn the Fluid oz and the weight oz… but other substances will be very different.

Fluid oz basically measured the same way you measure cups- a mark on a measuring cup. If it doesn’t indicate Fluid oz (often fl oz.) it’s weight. To measure weight oz you’ll need a scale.

(Guardian of the bacon) #5

To be brutally honest Tom…It’s a fucked up measuring system.


Fluid oz is a volume measurement vs weighing something, ie 16 oz in a pound.

In US cookbooks measurements are volume not weight.

So, when they say “fluid oz” they want you to measure the volume with a graduated measuring cup vs a scale.

(Tom Seest) #7

I’m out. I refuse to participate in such a messed up system…

(Guardian of the bacon) #8

Be a trend setter, go metric.

(Justin Blow) #9

Hey this standard system is good enough for Burma and Liberia, it’s good enough for the USA!

3 out of 196 countries… It truly is a stupid system…