Yeast harvesting issues

[chuckernorris]

I've been harvesting yeast and making hefeweizen over and over again, the last 2 batches I've noticed the beer tastes great after about a week but they start turning into gushers and bottle bomb shortly thereafter. I've made sure to be super sanitary so now I feel pretty certain I've just been harvesting yeast long enough for the yeast to evolve and last too long in the bottles, making too much co2. Anyone confirm this, I guess I'll stop harvesting, I always wash the trub to get my yeast.

 

[Homercidal]

Gushers and bottle bombs are a good sign of infection. The yeast simply cannot make more CO2 than the sugar can provide. Bacteria can eat other things as well, so they can continue making Co2 and causing gushers.

I've actually drank a gusher (what was left of it) and there wasn't an obvious flavor associated with it, it just tasted dry and fizzy. Not great, but not bitter/disgusting either.