A video posted to YouTube in January last year shows what happens when you mix Coca-Cola and milk.
Mixing the two drinks and leaving the mixture for a few hours creates a solid matter at the bottom of the bottle that you would only wish to serve to ISIS and Boko Haram folks.
The producer of the video gives a scientific explanation of what happened.
When you pour milk into Coke, the phosphoric acid in the Coke reacts with the milk proteins, mainly caseins, and creates a dense precipitate. The reaction involves Phosphoric Acid molecules binding calcium in the milk protein casein, to form a chemical complex that has a greater density than the rest of the solution, thus it precipitates out of the solution by falling to the bottom of the bottle.
The less dense liquid making up Coca-Cola and milk floats to the top. Thus, phosphoric acid effectively curdles milk protein.
You can curdle milk protein in the same manner by adding other acidic products, such as vinegar, grapefruit, and lemons.
Both milk and Coca-Cola are acidic, but Coke is more acidic due to its phosphoric acid content. Coke has a pH that ranges from 2.5 to 4.5, while milk has a pH of about 6.5-6.7, nearly neutral.
The acidic nature of Coke, due to the presence of phosphoric acid, explains why you can use it to clean tarnished metals like bronze and copper. You can also use Coke to remove rust from chrome fittings and degrease car engines.
But if you are thinking you would stop drinking Coke after seeing what it does to milk, the fact is that there are more important reasons why you may want to avoid drinking Coke. Probably thousands of people drink Coke after a glass of milk everyday and there is no evidence that it causes immediate harm.
Recent studies have linked the phosphoric acid content of Coca-Cola and other sodas to the development of osteoporosis in people who are not getting enough calcium from their daily diet.
The high sugar content of Coca-Cola is also potentially harmful. Sugar has been implicated in the development of diabetic illness, cancers and heart diseases.