Well good for you, jmatt. Wow. Does someone not have any sense of humor here or what?! I think some of what aquadoc says is probably correct, but I also think the major tobacco people like Greg who have looked at this for years are correct as well. And I don't doubt jmatt when he says that the one particular stain he looked at had some yeast growing on it. I think it likely that bloom has many different aspects to it depending on the tobacco and its composition. Not all bloom is powdery white.
But neither do I see yeast as a major unique flavoring agent of tobacco. Yeast grows on tobacco because it sees it as a food source. Various spots on the surface of aged stored tobacco have expressed compounds that might encourage minor yeast growth in some cases, but that is not to say that all bloom is yeast, but it would shock me if yeast did not occur.
But if yeast is occurring as bloom, then what has happened to the anti-fungal supposedly applied to many blends?
Also, for the record, it does not take a PhD to look through a microscope (or to even own a microscope!) and recognize yeast. Yeast is a fungi and pretty easy to recognize. So how has this fact eluded people like GLP for years? Nor does it make a logical argument that someone is right because they have a degree (many of us have degrees and many of the world's biggest problems are caused by people with degrees), or that they spend lots of money on their hobbies so they must be right. I spend a lot of money on my hobbies too.
Some facts would be nice here, but of course, it is easy to call people internet jockeys, claim to be totally right at the expense of all others in the hobby, have the proof, then go off in a huff saying that your feelings are hurt so you won't offer it to spite the group! I once caught a six-inch alien and wanted to turn him over to the Army but the Army didn't believe me! So I set him free.
Yeast is a fungus so if there were any significant biological activity in a stored tobacco from yeast, I think you would have significant outgassing of CO2. Some people claim swollen tins so maybe those are some cases of exceptional yeast growth? Something in there is fermenting. If that were the cases and if yeast were the cause of that and bloom then the next time someone cracks open a swollen tin, I'd like to hear them tell me it was full of bloom. It will be interesting to hear what aquadoc's analysis reveals.
As to the wine, Tim, yeast requires a sugar or some similar carbonaceous compound in an acidic environment. Does that rule out yeast bloom growing in non-virginia-based blends? Good question.