The Funny Thing About Ounces (oz. vs fl. oz.)
Today, we’re going to check jigger measurements to see how accurate the average jigger actually is. The think about free-pouring or using inaccurate cup markings is that it really throws off your drink recipes!
Note: We did this experiment way back in 2014, and at the time of publish, we weren’t making our own barware yet. Instead of taking down this article, we wanted to update it with our own, actual product.
Seriously, this experiment really affected the way we approached the style of jiggers, measurement markings, and capacity levels. Seeing countless jiggers fail the accuracy test just increased our desire to make the best double jigger ever!
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OK, back to the experiment.
Ounces are a funny form of measurement and can be difficult to explain. First, ounces can be a measurement of mass– or how much something weighs. Remember that 28 oz. Porterhouse you tried to eat at that steak house?
The other use of ounces is as a measurement of volume, as in the 16 oz. beer that you drink right when you get off of work, or the 2 oz. shot of Fernet you had with it.

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What’s even more confusing is that one ounce of liquid (fluid ounce or fl. oz.) is not equal to one ounce (dry ounce or av. oz., meaning avoirdupois oz) on a scale, and different liquids will weigh different amounts given the same volume.
I know, I know. I feel like I’m back in high school chemistry right now. The only conversion that we need to keep in mind when testing out the accuracy of common jiggers is that 1 fl. oz. of water weighs 1.043 oz. on a scale.
FYI, since my scale only goes down to the nearest 0.05 oz, I will be rounding to the nearest 0.05 oz.

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