Ringwood Yeast cake

Alright, so I racked a 2.5g IPA batch over to secondary last night, harvested the yeast cake, washed it, and added about 1.5 liters of fresh wort to get it active again. I plan on pitching it into a 5g baltic Porter batch this afternoon. My question is, should I pitch the entire starter (approx 2 liters), or will I be drastically overpitching? Its a cake from a 2.5 gal batch going into a 5 gallon batch, so I figured it would be just right. What do you guys think?

Anyone have any input? Should I use the entire slurry?

I'm guessing you have roughly 500-billion yeast cells from the previous 2.5 gallon batch. You didn't state the OG of your Baltic porter but according to Beersmith they typically range from 1.060 to 1.090. Assuming the highest possible OG (1.090) MrMalty says you'd need 320 billion yeast cells for 5 gallons.

If the above numbers are correct then you won't be over pitching by too much. I'd pitch the entire slurry!

On a similar note:

I pitched a smackpack of Ringwood yeast in a 4 liter starter ( I don't have a stirplate so I have to make bigger starters), let it do it's thing for a few days, then coldcrashed and decanted ( no washing to speak of). I now have a quart mason jar with about a 50-50split of wort and floc'd yeast. How long could I concievably leave this culture in the fridge? I suppose, as with any other yeast, I could leave it for a while, as long as I took viability reduction into account. Anyone done something similar and have any experience? I'm looking to do a clone of a Deschutes' beer with it, but may not be able to get to it very quickly.

Thanks for the reply! I did go ahead and pitch the entire slurry into the Baltic Porter, which ended up with an og of 1.080. Already churning away nicely! I didn't think it would be over-pitching too much, as the previous batch this yeast fermented was only a 2.5 gal batch. Just wanted to see if anyone had any suggestions. thanks again!