Re-activating Yeast Starter Prior to Pitching

[Bambooshoot]

Normally, after cold crashing a starter and then decanting off the starter beer, I just let the yeast warm up to pitching temps (48F for a lager), and then pitch into my cooled wort at the same temp (48F). However, I recently read a vague reference to the following method, which is not something that my prior reading had indicated:

- Decant off the starter beer
- Let the yeast in the flask warm up to pitching temps (48F for lager) while brewday is happening
- Once the new wort is cooled to pitching temps (48F), add some of this new wort to the yeast in the flask
- Let the yeast go to work on this fresh new wort overnight
- In the morning, pitch the whole flask into the main fermenter, which has been sitting un-innoculated in the fridge all night.

It sounds like a good idea to me because it gives the yeast a chance to get a head start on the starter before dropping it into the main batch. Is this a method that people use reliably? Any reason not to do it? Only downside I can think of is that the main wort will be un-innoculated over night and may be susceptible to infection.

 

[Fat_Maul]

I am not sure what purpose this would serve unless your wort was not oxygenated enough.

 

[Bambooshoot]

I guess I'm not sure either. Tasty McDole does it though so I assume there is a reason. Can anyone think of any advantages?

"On brew day (night actually) I pour the still "beer" off the starter and replace it with some of the wort I just made. I put the starter into the same 50F space as the fermenter and pitch the next morning when the starter is active and at 50F like the fermenter."

This was in a thread about his expedited lager fermentation schedule.