Hi ,
Hmm , not ideally ;
Part 1 : If you want to develop a seperate pithing strain ; Brew " Over Length " and cool the whole length as though it was ALL to the FV ; BUT , Reserve a seperate smaller FV and put the spare cooled wort ( Pref a re -sealable necked container ) and refrigerate at 4 c - 6 c until required .
Part 2 :
When your 1 St Dirty yeast head appears ; allow a good crown and then GENTLY SKIM THE DIRTY HEAD , AND don`t disturb the white foam below
( As gently as is possible ) .
THEN , On the Second Day , take allmost ALL of the Head OFF and allow to settle in a refrigerated area @ 5 c For 12 Hours in a sealed vessel , whenith as least ammount of headspace as possible .
Then at the evening BEFORE - 48 Hours before you brew , Take the cooled YEAST ( Remove carefully any DIRT , BEFORE USE & WORT and place the WORT IN A CONTAINER / small FV @ 25 c ; Then allow a small ammount of WORT into the CLEANED YEAST BED , and thoroughly mix / blend , add fractions more WORT , then once a reasonably liquid is there , add to the other WORT @ 18 - 22 c and thoroughly shake / Oxygenate the WORT .
Allow @ 18 - 22 c For say 2 days , under observation / alter to requirements .
Hope that helps ,
Edd