You might have noticed that they don't sell carbonated milk in your area.  There's a reason for this, and the reason is that carbonated milk is disgusting.  No one in their right mind would ever drink it, let alone make it.  Consider: carbonation is intended for sweet, sugary water, which every parent will tell you is the direct opposite of milk.  The anti-milk, if you will, warned against in the Milk Book of Revelation.  But as everyone knows, carbonation makes things fun.  And one day I was in bad need of fun.  Should you find yourself in a similar situation, for god's sake, don't do this.  If you succeed it's gross.  If you fail it's dangerous and gross.

I knew this, but I was a headstrong lad, and I wanted carbonated milk.  I went to the stores, which had so rarely failed to validate my existence or shore up my sense of self when I was feeling empty.  Alas, today I was on my own.  Frustrated at my local Quality Dairy's lack of fizzy cow products, I decided to make my own.  That fateful day I stumbled upon The Recipe, which I have kept to myself these long years, waiting for a worthy reason to share it.  Among such peers, I can no longer keep this secret from the world.

Should you be stupid enough to decide to do this, you will need:
  1. A fairly new 20 oz. bottle, like they sell Coke in.
  2. A small handful of dry ice, crushed.  (Note: do not try to measure this with your hand.  Dry ice will burn you.  Get your younger brother to do it.)
  3. Some milk.  A little less than 20 oz.
  4. Protective eyewear.  Or a ready emergency room and a plastic baggy for your eyeball, which will pop out when the cap is violently ejected from the bottle into your eager, innocent face.

The dry ice is the only ingredient that may be hard to come by.  For all their recalcitrance when it comes to offering sparkling milk, Quality Dairy was remarkably willing to hook me up with the wherewithal.  You probably don't have a Quality Dairy in your town, unless you live in Lansing, so I'm afraid I can't help you much with your ice shopping.  If you live in a research university town, you may be able to get dry ice from the Chemistry Department's stores office, which receives a lot of reagents on dry ice.

As you've doubtless guessed, you're going to make something that bears a creepy resemblance to a dry ice bomb.  However, your goal here, and I know this is strange, so bear with me, is not to cause an explosion.  Your secondary goal is not to blame me if you decide, in spite of your common sense and what I'm telling you right now, to go ahead with this.  That said:

Go outside.  Should anything go wrong, there are fewer things to saturate with milk.  Crush the dry ice and add a small amount to an empty 20 oz. bottle.  I probably used a total volume equal to my pinky.  Now, add the milk.  To minimize the chance that you'll pop the bottle, keep your milk as cold as possible.  This will keep the carbon dioxide from being released in an explosive rush.  Also, the more you fill the bottle, the greater the pressure you'll put the milk under.  More milk gives you more carbonation, but also increases the chance of catastrophe.  After you've added the milk, cap the bottle and step the hell back.

The dry ice will sublimate.  In the confines of the bottle, carbon dioxide will be driven into the milk.  It will go spelunking.  Wait a few minutes, or until your curiosity overrides your better judgment.   If your bottle doesn't pop, good job.  Unscrew the cap (carefully.  Do NOT point the bottle at your face.  Contents under pressure, may explode and maim you, etc. etc.)  Congratulations.  You are now the proud owner of 20 oz. of undrinkable, bubbly crap that tastes like ashy chalk.

Thanks to Professor Pi for reminding me that full bottles are more dangerous and noting that this SHOULD NOT be done with glass containers.

Eraser_ says: any truck stop will sell dry ice by the sheet.  It's like 20$ for a whole lot of it.  Bring a cooler.