If yeast grows exponentially, then surely it should be possible to virtually eliminate undesirable yeast strains from a yeast supply simply by propagating it a number of times.
Eg. If I have a yeast supply that contains 90% of the yeast I want and 10% yeast I don’t, when I add this slurry to a starter, both yeasts grow exponentially to the point where the dominant yeast dominates at a higher percentage. If I were to take some of that new slurry and put it in a further starter, I should be able to get to a point where the yeast I want should be 99.9% dominant.
Has anyone got any experience or research to back this up?