This came from a microbiologist down the street:
When she was in college in Colorado, students there wanted to brew Coors-like beer. So they wrote a letter to Coors requesting a sample of their yeast. Coors very politely replied with a letter explaining that the yeast was proprietary and ….. That was expected by the students because the reply was contaminated with Coors yeast. The clever students isolated the yeast, cultured it and brewed their beer.