Saturday, 15 October 2011

Got Milk?

I woke up this morning and had some coffee.  I make coffee with a press so with the right amount and time the coffee can be quite good.  My girlfriend usually adds milk to her coffee.  If I am in the mood I will add some however mostly I prefer it unpolluted.  Around the expiration date she might sniff it then drink a little before adding it to the coffee.  A couple of times after drinking she could taste that the milk was a bit off.  Also she mentioned at different times of year the milk quality changes for the same brand of milk.  So I was wondering whether you could measure surface tension of the milk to get a quick estimate of the quality.  Is this possible?

Yes.  Milk has  a lot of different surface active proteins and fats making a colloid in water.  The surface tension of pure cows milk depending on the cow, the season and other factors could be around 52 dynes/cm.  However, if the milk sits for a while and certain these proteins break down after a phase seperation of the colloid suspension the milk will decrease in surface tension to 35 dynes/cm.  Milk is an important source of protein for much of the world's population.  By understanding the properties of milk and preventing the separation and subsequent change in the milk from good to rancid the milk could be distributed better.  Also it one might learn which cow is better at producing milk and optimize the conditions for those cows..... Just some ideas what surface tension might allow you to do.

Hell, I don't even drink milk. I just like these splash photography pictures.