Sourdough bread culture is much the same, I have one that has kept going now for 3 years.
I bake every 2nd week and refresh the starter, after 3 days growing it goes in the fridge. Keeping the ferment below 10c keeps the "sour flavour elements" under control, so my bread is only very slightly sour.
Natural everything is best, processed bakers yeast is much more active and aggressive, but in my view the resultant bread is harder to digest. Commercially yeast us used for speed, my bread can take 12 hours between mixing and baking, so the dough develops SLOWLY!
