Pouring Wort onto Used Yeast Cake...

I've never done this before, but I'm planning on doing it this weekend. My question is, I've left the cake sitting in the carboy (sealed) since Sunday when I racked off of it...so would it be helpful to pour a small starter batch into the carboy the night before I brew? Or is this unnecessary? If it hadn't been 2 weeks since the original pitch, and it hadn't been sitting alone for a week, I might not be so concerned, but in terms of decreasing lag time as much as possible, wouldn't a small starter poured onto the cake the night before serve to jumpstart the cake? Or is this completely unnecessary?

That's a really good question. Have to admit, I thought of that myself a couple of times as I'm interested in reusing yeast as well when I make the switch to liquid yeast. Hopefully the "pros" will kick in here, especially brewpastor, he used to own a brewery. I've read several arguments for/against using yeast cake with old trub. Some say it will affect the brew, some say it doesn't. I would think that if your making the same type of brew, it really wouldn't matter.

If you're repitching using the entire yeast cake form a previous batch, I think you'll get a pretty fast and vigorous start without any sort of starter.

Make sure you have a blowoff tube rigged for this one--you're probably need it.

Just go in right on top after you cool it, just make sure you have a blow off tube or a lot of head space. It's going to go crazy....

shiezer! The only blowoff tube I have is an emergency one...just hook up a standard racking tube to the small nub on a carboy cap. But I do need to go to lowes tonight. Anyone have any idea what the ID/OD of a standard large blowoff tube is? I really don't wanna have to lug my trub-filled carboy into lowes.

Also, anyone know whether or not it's okay to use the cake from a Wit (with orange peel and corainder in the boil) on a hefe? I'm sorta worried that some of those flavors might transfer from the trub into my hefe.

1 1/4 inch OD tubing fits perfect. Heat the end up with some hot water before sticking it in the mouth of the carboy. It will seal better this way.