Greeking my yogurt

I haven't gotten a new yogurt maker yet, so I'm just buying the big containers of plain yogurt at the store so I can sweeten/flavor it myself.  (Olivia would prefer to eat Yo Baby but I think that's because she likes the little chef baby on the packaging.)  Once I stir the container of yogurt to incorporate the liquid (whey?) the yogurt stays kinda runny, so I decided to try to strain it to make Greek-style yogurt.  Greek yogurt is thicker, and the brands at the grocery store are fat free and tend to sweeten with sugar or honey instead of aspartame or, heaven forbid, high fructose corn syrup. 

Since Greek yogurt (yogurt cheese) is really just thick yogurt, I just needed some sort of strainer.  In my yogurt maker research I came across a device made just for this, but reviewers mentioned difficulty cleaning, rust, and the need to empty the container during straining.  Pass.  Cheesecloth, ironically, seemed to be too loose of a weave and I could picture it soaking up too much of the good stuff.  Tapping into my memory of chemistry lab filtration, I figured a coffee filter might do the trick. We have a small gold coffee filter for our old coffee maker, but I was worried that it wouldn't be a fine enough mesh for yogurt, so I cut down a #4 paper filter and set that in a mug.  (Mug is from Earthworks in Barbados, for those who are curious.)  Filled it up with yogurt, set it in the fridge for a few hours, peeked to find success!  Creamy consistency like frosting.  My only complaint is how much volume you lose in straining.  I read online that it is reduced by half or more, depending on how long you let it strain.  No wonder Greek yogurt packaging touts that it has twice the protein of regular yogurt. 

The next try was with our "camping coffeemaker" which is basically a filter basket that sits on top of one's enamel camping mug, to be filled with coffee and water that tastes suspiciously like campfire.  Here is the before and after so you can see the volume change.  No, I did not measure. 

Add some honey and granola and it's delicious.  My question now is what is the nutritional value of the liquid that I'm dumping out?  What do you do with your whey?