Thanks for your reply and explanation what you're trying to do with your experiment.
First off, the term 'contaminating' is indeed misleading. You haven't misled me per se, but potentially other members, especially those who are not familiar with starters, sponges, poolishes, etc.
What you have done in your experiment would probably qualify for the term of “Fusion” not “Contamination”.
Contamination is explained as:
a : to soil, stain, corrupt, or infect by contact or association <bacteria contaminated the wound> b : to make inferior or impure by admixture <iron contaminated with phosphorus>
: to make unfit for use by the introduction of unwholesome or undesirable elements
contaminate, taint, pollute, defile
mean to make impure or unclean. contaminate implies intrusion of or contact with dirt or foulness from an outside source <water contaminated by industrial wastes>. taint stresses the loss of purity or cleanliness that follows contamination <tainted meat> . pollute, sometimes interchangeable with contaminate, distinctively may imply that the process which begins with contamination is complete and that what was pure or clean has been made foul, poisoned, or filthy
<the polluted waters of the river>. defile implies befouling of what could or should have been kept clean and pure or held sacred and commonly suggests violation or desecration
I started out by making a commercially yeasted (IDY) starter. I made a poolish with 50/50 water and AP flour with a bit of IDY. I then let it become active within 6-8 hours, dumped out half and fed it with 50/50 water/AP flour. I did this several times until I got an active starter after several hours of feeding. I tasted the IDY starter at it's peak and it had ZERO flavor. No hint of any sourness whatsoever.
No starter should contain any commercial yeast to begin with, whatsoever. But you said you made a poolish.
A starter is only made from flour and water. A poolish is basically the french equivalent of a sponge, not a starter. It's wet with an equal amount of water and flour and usually contains a small amount of commercial yeast.
A starter is a mix of wild yeast, flour, water and bacteria and is fed on a regular basis. I'm saying this just to clarify for the members who commented on your experiment as to not confuse them. Especially new members.
I hope that helps to explain your experiment a bit better for other members, including myself. I'm not trying to ride your derriere but I have been corrected numerous times if I got terms wrong, explained things the wrong way, etc... for the benefit of others, which I have always appreciated since I learned from the corrections myself.