How big of a pot for BIAB?

I currently have a 7.5 gallon pot that I've used for both extract kits I've made. It seems like the BIAB method is the easiest, cheapest way to make the transition to AG, so I'm thinking all I really need is another pot. What size should I get for 5 gal batches?

The pot you have will work just fine. I made many batches in a 30 qt pot before making a cooler-based mash tun. For sparge water, 20 quarts will be plenty.

Oh ok thanks. I had viewed one of the tutorials and they used two pots, one for mash, and one for sparging. Basically dunked the bag into the sparge after draining into the mash. Thats what I had in mind when I asked about the second pot, because it seemed like you would be combnining the two pots into one and wasn't sure if the 7.5 gal was big enough for that. How do I sparge with just one pot?

7.5 Gallons might be a tad small for the Aussia BIAB (one pot) method.

I use a 42Quart (10.5 Gallons?) for a standard 6 US Gallon batch, and have only 2 or 3 inches of headspace by the time you get the preboil volume + grains in there.

I picked up the pot & burner for under $100 at walmart and it works great!

"I picked up the pot & burner for under $100 at walmart and it works great"

Great thanks!

Don't want to dispute what others have said b/c they are correct; a 10-gallon or so will make your life easier for a 6-gallon BIAB. That said, I have done one with my 32-qt. I did this:

1. Heat mash water in 32-qt pot. Mash in a bag.

2. During mash, heat sparge water in several pots on the stove and dump into a bucket (i used a bottling bucket)

3. Pull out grain bag and sparge in the bucket (not quite the Aussie method, true)

4. Dump bucket contents into 32-qt pot with the 1st runnings

5. I had about 7 gallons collected when i started the boil, so it WAS very full. But with Fermcap you should be able to avoid boilover.

So it is possible with what you have. Easier with a bigger pot though.

What about a minimash? How much grain vs extract could I comfortably do with a 32qt pot and a 10qt pot?

This calculator will help you determine how big of a pot you need for a given mash.

Hmm, so at 1.25qt/lb, i could mash approx 6lbs of grain in the 10qt pot, and use the larger 32qt pot for the sparge, then remove the grain, combine the liquid and boil, adding extract.
If i went with a stiffer mash (like 1qt/lb) would that work? (I assume at a lower efficiency).

I would not go less than 1.25 qt/lb, it will be too thick. I just did a small batch BIAB last night with a little over 7 lbs of grain (big beer 1.096) and something I would note to you is that the grain bag gets really heavy when draining, even with 7 lbs. I used a large cookie rack to put over my BK to let it drain during my boil and it worked well.