Originally Posted by whoaru99
I probably wouldn't put 500ml of starter juice in a 1 gallon batch. I'd put the starter in the fridge for a few days to floc out the yeast then decant off most of the liquid, swirl up the remaining liquid and yeast cake into a slurry, then take out what you need for the other batch. Then put your wort onto remaining slurry if you're confident the container is still reasonably sanitary.
My time table didn't allow me that kind of time. I decided to brew Sat as I knew I would be cooped up in the house all weekend, so as the first snow started on Friday I made a mad dash to my LHBS to get what I needed. I made the starter (my first) Friday evening, so it was only about 18h old or so when I pitched. It seems to be working ok as the 2L portion of the started was fermenting strong enough to blow the airlock off the 4gal batch in a 5gal carboy, and the one gal batch is bubbling happily away.