The year is 1487 and you find yourself in the German Empire.  You happen across a brewer and ask him what is in his beer.  His answer: “malt, water, and hops.”  Of course we now know that yeast is a critical fourth ingredient but in 1487, before the microscope, fermentation was the stuff of magical pixies and fairy dust.  Back then the law known as the Reinheitsgebot dictated that beer only include malt, water, and hops. 

 
Today, we include all kinds of stuff in beer.  Most of the time these adjuncts are used to create interesting flavor profiles that may or may not fit a defined style.  That’s all good as far as I’m concerned, but there are some other additives that may surprise you.  Check out this list of beers that use everything from artificial coloring to genetically modified ingredients.