3L of yeast needed, but only a 2L flask

[Yesfan]

I'm hoping to do a 10 gallon batch this weekend. The beer is a light pale ale with a 1.045 OG. Mr Malty tells me for 11 gallons of wort, I'll need 3.7L of yeast. I have a little more than 2L on the stir plate now, in a 2L flask. Can I just decant the spent wort, and dump fresh wort into the same flask or do I need to go ahead and store the first starter in a sanitized jar?

Also, will I have a blow off situation with the volume being slightly above the 2L mark? I started with 2L or water and 8 oz of wort hoping it would boil down to around 1800ml. I guess a 5 minute boil wasn't long enough.

The yeast is 1056.

 

[Snicklefritz]

Check out this calculator:
http://www.brewunited.com/yeast_calculator.php

It will figure out all the steps for you. No need to store in a jar. I just cold crash and decant between steps. As for blowoff I highly recommend Fermcap-S for starters. After a few too many starter explosions I've learned my lesson.

 

[d3track]

Crash, decant, add wort

 

[JosephN]

I have recently, last week to be exact, did the same thing and I just crashed it, decanted and pitched more wort on top of it and it came out pretty huge. Basically a lot of yeast. Give that a shot and if you get the results like I did you'll be very happy.

 

[JosephN]

Oh and one of the starts I made, which I made two different ones, one was 1056. I have a super creamy krausen right now and I wished I could pull some out of my carboy to harvest while its fresh but I haven't thought of a way to do it with such a small opening.