The German Purity Law, or Reinheitsgebot, was originally enacted in 1516 and is the oldest food or drink regulation in the world which is still enforced. "Reinheitsgebot" which is pronounced "Rine-Hites-gaBoat" essentially means "purity law.
The original rules allowed for just three ingredients to be used in the brewing of beer ... water, hops and barley malt. In the 20th century, yeast was also added to this law. The law guarantees that any beer brewed within the borders of Germany is a pure beer without any additives.
It does not apply to German beers brewed outside the country.
When you see a German beer that states that it is brewed in accordance with the German Purity Law, you know you are getting an all natural beer.
An excellent law in that it does not allow for the chemicals that North American big breweries use in their beer, it is also a very restrictive law which would not allow for wheat, fruit, herbs or spices to be added to the recipe, all natural ingredients which are being used to create different line of flavorful beers.
I would like to see some sort of law or rule be applied to Ontario/Canadian beers so there would a clear definition for consumers of what was an "all natural" beer and when the term "all natural" could be used in advertising. One that would allow brewers to add other all natural ingredients to create new flavors of beer but guarantee to the buyer that a beer contains no other additives.
"All natural" currently is being shouted in big brewery ads to describe the spring water used. To my way of thinking, the term should only be used to describe the product as a whole and not just one ingredient.
From very early on, Germany was onto something in protecting the way beer should be brewed.