Mark, I've suspected that for years but have never been able to verify it. How did you find out?
I assembled bits and pieces until a clear picture emerged. The first clue was in the BrewTek description for CL-50.
CL-50 California Pub Brewery Ale
For that classic U.S. small brewery flavor. CL-50 produces terrific American red & pale ale styles.
While attenuation is normal, this yeast produces a big, soft, well rounded malt flavor that really lets caramel malt flavors shine.Jeff Mellem told me that the culture came from a brewery in Northern California when I inquired about it (I started purchasing yeast on slant from BrewTek before CL-50 was added to the collection). Jeff told me that he had acquired the strain from someone who acquired it directly from the brewer. I pushed him for the source, but he would not budge. The only amber/red ale that fit that description was Red Seal Ale, but I needed to rule out Mendocino, which I did by plating and brewing with Mendocino's strain.
Later, I read an article where Mark Reudrich stated that the strain came from UC Davis. Mark had experimented with several UC Davis yeast strains before settling on the strain that became North Coast's house strain.
Throughout the years, I encountered more evidence that pointed to North Coast as the source of CL-50, but what solidified things for me was a post made by a guy who went by the username "hopheadca." His posting matched what Jeff had disclosed back in 1995 as well as what Mark had disclosed in the article.
http://www.brewboard.com/index.php?showtopic=67897&st=0&p=847286&#entry847286"It has been a while since I have spoken /Mark. I first got the yeast from him in 1995. I gave it to Jeff Mellem, who at the time ran a shop in southern CA. He and Maribeth Raines turned into the Brewtek CL-50. According to Mark the strain came from the old yeast bank at UC Davis.
As I said, just give Mark a ring. That's what I've done. He's a good guy. He won't tell you exactly, but will usually give some good pointers. My clone of Red Seal Ale has wone numerous awards."
As one can clearly see, the thread was not about CL-50. It was about cloning a North Coast beer.
As an aside, I have been attempting to identify the original UC Davis accession number for the strain. The problem is that the UC Davis culture collection went through a revamping where all of the accession numbers changed. For example, UCDVEN 854 used to be in the main culture collection (known as the Phaff Collection today) with the accession number FST A47. There are now two separate culture collections at UC Davis. I wrote a blog entry about the UC Davis culture collections for anyone who is interested.