View Full Version : By volume or by weight?

07-24-2009, 12:50 AM
I was just playing around with this tool...


At the bottom, it gives you two alcohol measurements: 1) by weight; and 2) by volume. For example, my current batch (which is far from being finished, and I'm just playing around) measures 3.7% alcohol by weight and 5.1% alcohol by volume.

I'll be honest, I'm having a little difficulty getting my head around the difference. Can anybody shed some light on this for me?

07-24-2009, 02:14 AM
Alcohol, by it's very nature is less dense than water. My memory might be bad but the figure that sticks in my leaky memory is that 1oz of water by volume equals 1.25 oz of alcohol as far as weight goes.

It's a density issue. H2O is more dense than CH2HO5. If you want to measure by ABW (like some very few states do) you can have a 3.2% beer. But if you measure that same beer (mead, or whatever) at 3.2%ABW, it will be 4.0%ABV. ABV has always seemed like the better measure to me.

I know that when I choose to indulge, the weight of the alcohol has been of minimal concern. It's more a matter of the VOLUME!

Dan McFeeley
07-24-2009, 10:36 AM
A few more details can be found at these links: