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I've seen numerous recipes that call for measuring "liquid ounce" but at the same time telling you to measure something like flour as "dry ounce" - I've even seen references to "fluid ounces". Are they interchangeable when measuring ingredients? If not why, if so why separate the two types of measurements?

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1 Answer 1

Both liquid ounces and fluid ounces are the same. They are a measure of volume. These are commonly called liquid measurements. These include: teaspoon, tablespoon, fluid ounce, cups, pints, quarts, and gallons. Why fluid? Because it's measuring volume.

The term "dry ounce" is one I have never encountered. It's rather confusing and misleading. Technically a dry ounce would imply a measurement of weight. 1 oz = 28g.

Your recipe could be calling for a measurement by weight of flour, or it could be using a terrible phrase "dry ounce" to imply that you should measure the flour with a measuring cup used for dry measure, as opposed to a measuring cup used for liquids.

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This is absolutely right. One more valuable thing to know is that for water, an ounce by weight or volume is (very close to) the same. So if you are in a situation where you are estimating, and the thing you need to estimate is similar in density to water, you can treat them effectively interchangeably. –  Michael at Herbivoracious Sep 5 '10 at 22:08
What do liquid measuring items look like or what are they called? I feel like all I have are measuring cups (either plastic or glass)... –  Rhea Aug 3 '11 at 21:25

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