We're walking home from the corner store the other night with a gallon of water, a gallon of milk, and some beer-  my wife and I couldn't agree about which weighs more:  a gallon of milk, a gallon of beer, or a gallon of water, assuming equal volume, packaging weight, etc.

I hypothesized that the beer weighs the least (air bubbles and all); the milk was in the middle (it contains fat, which is less dense than water); and that the water would be the heaviest because it is the most dense.

My wife has no clue about this shit, but she doesn't agree with me.  She thinks that the water would be the lightest, then the beer,  and then the milk.  Anyone have any hard evidence here??

which feels heavier when you drink it? hehe

As the resident homebrewer and chemist ta boot, I can answer the beer and water part.  

Depending on the type/brand of beer, the final or finishing specific gravity is somewhere above 1, usually 1.001-1.005.  Since SG is a comparison with pure water, beer is heavier than water.  BTW, SG measurements are used to determine alcohol content and watching it change is the indicator of fermentation process.  When the SG stops changing, fermentation is over.

Milk is the heaviest due to dissolved proteins.  The fat slightly decreases the SG but the solids increase it.

Use a radiator, or battery tester. It'll tell you the specefic gravity of the liquids.
The Beer should be the lightest, followed by Milk, then Water..

Meplat-

Your normal everyday gallon of water. Such as distiled water or drinking water will weigh about 8.3 ppg. pounds per gallon.  Don't know about beer or milk since i never ran those through the densitometer on my cement pumps. Don't know if that will help ya very much, but there it is fer ya.

Whole milk (3.5 % butterfat) = 8.6 lbs./gal.

What a shocker! Milk=8.6ppg, Water=8.3ppg, and beer is somewhere in the middle.  No wonder my wife never wants to carry the beer!

well next time just buy light beer....[beer]

[beer] only one way to figure this out for sure

We used to throw light beer into a pool and swim around.  If you bumped into one you drank it!  They just barely float.  Real beer goes to the bottom!  So does milk.

that sux!!!!


YOUR WIFE WAS RIGHT!!!!

So light beer floats, real beer is heavier than water, as is milk.  From what one guy said already, regular beer is just barely heavier than water, so it makes sense that light beer would be even less dense.  

But, with the cans/bottles floating in the pool, some of that could be attributed to the air in the container making the beverage more buoyant.  In addition to that, the water could have had a slightly more saline content, which could have made the stuff float better.  I've thought about this for too long already...