24 Qt is 6 gallon, for an extract batch this will be ok.....because after the boil off you can top off with water but for Ag its really not, for 5 gallon AG you really need to start with about 7.5 gallons or 7 gallons of wort to make up for boil off and cold break, but if you are doing extract just watch the hot break like a hawk.
I would highly recommend buying a 10 gallon pot now if it's in the budget. If you decide to go AG or even want to do five gallon extract full boils you will wish you had the bigger pot. I ended up getting a smaller one, and still had to buy a big one for my AG conversion.
You can pick up a decent aluminum stockpot for around 50-60 bucks at outdoor stores, online, or sometimes at Home Depot/Lowes or other big retailers.
I wasn't planning on doing any AG brews just yet. I just wanted to know if I could get away with a 5 gallon extract boil with only 1 gallon of space left in the pot. A 10 gallon pot would be ideal, but I'm using an electric range and I think a 24 quart pot is pushing the limits. I live in an apartment so room is pretty limited, especially with the equipment I already have. I don't think I have enough room for a stand alone burner and gas tank.
I just upgraded to a full boil on my electric stovetop. They key was to use an aluminum pot (SS didn't get hot enough), and an insulation blanket. I got 6 galllons to a rolling boil easily in my 30 qt pot. See my post here.
Also, generally speaking you want a pot that is at least 50% bigger than the volume you intend to boil down to because you need to accommodate for the extra volume that will be evaporated off during the boil, plus a bit of room (to avoid boil-overs). Twice the size is even better, although if you use foam control (e.g. FermCap) then you can easily get away with a smaller pot.
Thanks Flyguy, I was actually looking at your post earlier and was pretty excited to see that a crappy stove like mine has the potential to boil 6.5 gallons. I wasn't sure if that was just 6.5 gallons of wort, or water, that you were talking about. Maybe I'll go for the 30 quart, I'm just wondering if I can get away with having only 1.5 gallons of boil off?
Get the largest pot that you can afford. You will thank yourself for it later.
I did quasi-full boils in a 22 qt. pot for a while. I'd get 5 gallons going then about halfway through the boil after some boil-off I'd put in what I had left from the last sparge. It worked out ok, but man was it a PITA.
I had a 7.5 gallon pot for my extract brews, when I switched to AG that just became my HLT.
I say get whatever you can afford now, but either get something big enough (10 gallon) to use for full boil AG brews later, or get something smaller that you can still use for your HLT...
+1 on getting a bigger pot, if you ever think you will graduate to AG. i don't know that full boil is really that significant for extract - but it's worth researching to see if there's a big advantage.