Additionally, recipes change overtime to accommodate any number of environmental factors: better tech, lower or higher cost/availability of raw materials (e.g.

Additionally, recipes change overtime to accommodate any number of environmental factors: better tech, lower or higher cost/availability of raw materials (e.g. bad harvest, war). One benefit of keeping the recipe 'secret' is ability to continually tweak it. So, it's more a question of the recipe from when (and perhaps even where). This is very evident in the history of beer. Here's just one small example: http://barclayperkins.blogspot.com/2013/02/tetley-porter-1858-1896.html http://barclayperkins.blogspot.com/2013/02/tetley-porter-185... Same beer across 38 years; changes in ABV, changes in hopping, changes in boil time.