Reusing yeast for higher grav beer

I have a quick question....

I've recently brewed a beer with a starting grav of 1.048. I made a starter from a Wyeast activator smackpack for this. I made a 2 quart starter for this smackpack and pitched that into my beer.

I haven't racked to a secondary yet, but it occurred to me that I could probably rack to a secondary and drop a higher grav beer (1.1 ish) right onto the yeast from my 1.048 beer.

I'm sure that this is probably a bad idea, I just don't know why. I figured I increased the cell count when I made the starter to 200 million cells, and that is sure to have increased when I pitched it into 5 gallons of wort. I am also diligent about sanitary conditions so I figure I'll be okay there.

What do you guys think about this (probably bad) idea?

This is a very common method.... not a bad idea but rather a good idea as long as you want the same yeast profile for this beer. As long as you know your yeast is healthy by not being stressed from an initial high alcohol beer or a very very long time in the primary you should be awesome. Often brewpubs will ferment a 5gallon batch and then use the yeast cake for their brewing purposes.

This is a very GOOD idea. We call it 'pitching on a cake'. That's how I do all of my big beers. Think of it as a 5 gallon starter.

Awesome, thanks!

Watch your temperature though. Maybe it's just me but whenever I pitch onto cake my beer ferments hot even with the swamp cooler and A/C. Vigorous fermentation produces a lot of heat, I guess.

Yeah, I repitched a RIS onto a cake of US-05 from a brown ale and had VIGOROUS fermentation going in 10 minutes and 4 inches of krausen in 45 minutes. Definitely use a blow-off tube for that one. Totally fermented out the 1.136 wort in about 5 days.

It is a good idea. It is basically creating a 5g starter! I just did this for a barleywine.