quick yeast washing?

[manisfive]

I am brewing this weekend and have a yeast cake that I would like to use for the brew session. I haven't racked off of the cake yet. I am trying to avoid doing a starter. I am doing a small belgian beer and don't want to risk over pitching. Is there a way to harvest the yeast from the cake with out washing it while actually getting the right amount per a pitching calculator? I don't want to screw up my beer. I am operating on a single keg system and I don't want to risk having a crappy beer in my single keg.

 

[Pkrd]

Here's what I do...
After racking the beer off put 1L of boiled and cooled water on top, shake it up, pour it off into a jug.
Let the junk settle out (the yeast stays in suspension much longer) for 10-15 minutes and pour off 1/3 of the liquid on top, pitch that.

 

[WoodlandBrew]

Cell density of harvested yeast can range from about 1 billion cells per ml to 4 billion cells per ml depending on your process.

All grain, dumping everything from the boil kettle to the fermenter is 1-2 billion per ml. If you whirlpool and don't dump everything it's closer to 3 billion per ml. Extract with no steeping grains is about 4 billion per ml.

These are all volumes of settled slurry.