How can you tell what strain / type of infection?

I quite liked the few sours that I have tried, and want to eventually start brewing my own properly, but a recent infection had me accelerate my learning curve. One of the questions that I cant really seem to find an answer for is this:

Is there any way of determining what bug has gotten hold in your brew by its appearance?


p.s. the main reason I ask is this: separate thread here.

 

IMO, there is not a reliable method to identify an infection based upon morphological appearance only; there are too many variables. In addition, identifying if it is objectional or not is even more difficult. A pure culture of an organism may not even appear the same in two identical conditions.

The easiest to identify is the filamentous fungi (molds). They are fuzzy. But other than that, all bets are off. Bacterial infections can look just like Brett from what I have seen...