Over pitching

[stosh]

I brewed 3 gallons of an Irish Red yesterday and due to distraction pitched most of the 2 liter starter I made.

I'm curious at what point has a brewer over pitched and how much can you over pitch before it becomes problematic?

 

[Gnomebrewer]

It's very hard to overpitch, to the point of detriment, from a starter. You've probably put in double what you needed, but it won't hurt. It's easy to massively overpitch using fresh slurry though (from a previous batch). I have a theory (actually a hypothesis) that overpitching reduces the lag phase, resulting in yeast starting fermentation too soon instead of fully lowering the pH, meaning a higher final beer pH. I don't have anything to back this up though (it really is just a hypothesis). I've been wanting to test it for the past year, but have been way too busy (lazy).

Edit: Your biggest off flavour will come from 2L of starter in 12L of wort - that means about 14% of the finished beer is actually starter.