patigyle has a lot to do with volume... it uses a ton of grain to get a high OG wort from the first running (like natty said)... with only two or three smaller volume runnings combined to get a lower gravity second beer... we're all in agreement on that.

but, here's where my thoughts differ (and these are just my thoughts... take it for what you think they're worth)... if you do a full volume BIAB mash, then there's not much to go around for another wort since you're getting all the "volume" that the gravity points can fill out of the way in one go... if that makes any sense.

if OP does a large grain bill in the first BIAB then yes, it *might* work... similar to what natty and CF suggested. but i'd bet if it's just a regular old full volume BIAB, then put the grain bag in a second pot with a full volume of strike/mash/sparge water, there wouldn't be a lot of sugars left to get a good gravity in a new pot of water. it's a good idea... i feel like there's left over sugars i'm getting when i do BIAB, too. but unless you "sparge" in the second pot and add some DME to hit a high enough gravity... i don't think it'd work. but like i said, that's just my thought.

I totally agree.

However if you are NOT full volume your second go around would be like a sparge of the grain for a weaker wort. Combine the two and there you have it.

Thank you for all of the help, it sounds like this is maybe but I am definetly going to give this a try saturday morning and see what happens. Professor I am shooting for a Big Beer and then a Small Beer effect. The BIAB method is pretty easy and its great on space as I live in a condo. PSUChunk, I definetly understand what you are saying, but now another question has come has arose. Could I use fruit or something to "cheat" along with the DME/LME to get more sugars? I ask about the fruit since it's going to be a small beer I might as well make it for my wife...

A lower OG beer would be thinned out by the simple sugars that a fruit addition would bring to the mix. I would keep some DME on hand to get the gravity up in case the second wort isn't as big as you're hoping for... Then do a drug addition once the OG was high enough to support a simple sugar addition.

What about overshooting the volume on the "first runnings", then blending some of that with the weaker sparge water?
Example (these numbers are totally made up and not realistic!):
Make 3 gallons of 1.070 wort. Sparge 1 gallon and get maybe 1.010. Take 1 gallon of the 1.070 and add to the sparged gallon and get 2 gallons of 1.030.
Just a thought.

Here's a thread that may give you some info:
"Saturday I did 2 batches, attempting to get a higher gravity (brandy wine) and a mild. I was shooting for 10 gallons total, but wanted a milder brew at around 3-4% that I could drink in a 2-3 weeks, and a heavier beer to age for several months like a brandywine."
BIAB Parti-gyle

nice...I had been looking at like a dozen similar threads "over there" as well! seems like a decent idea, and I'm gonna try it later on this year (got 7.5 gal conditioning, slew of single bottles, and a combined 3 gal at least in my kegerator, along with ingredients for 5 more gallons just sitting here waiting! hmmm...MBFans party at my house?) when I've got the time/brew room to do so!

It appears this method does not work

Nah, it definitely works...your small beer had a gravity of something like 1.032, right?

Because that's definitely in the realm of what people are looking for when they go partigyle.

Well I tried it and now I'm just relaxing and not worrying about what's in the closet, i'll try it in two weeks...