40 gallon kettle biab

New to this whole brewing gig. My buddy and I do strictly biab at the moment. He went out and got the blichmann 60 quart. I found a steel on a 40 gallon stainless kettle. I think his blichmann is 15.5" across. Mine is only 19. Im never going to be doing anything smaller than 5 gallon finish sizes. Some traditionalist that I talk to are saying my surface area is to large to do 5 gallon batches. But with only 3.5" different than the popular blichmann I find this hard to believe. Is there anything I should be concerned about? I've got better things to spend my money on with this new hobby than a smaller kettle !

Thanks!

You will just have a larger boil off rate. You will just need more pre-boil volume to end at your target amount. A couple test runs of just water will help you understand how much you boil off an hour.

Yes! That's what I told him. Setting up my pot in beersmith and going to do a boil off rate next week once my sight glass is installed and my banjo is running. He said that produces off tastes.. thanks for confirming!

Some beliefs are outdated. Make a batch with your new kettle, pitch enough healthy yeast, control your temps and prove him wrong!

Wait - "new to the whole brewing gig" and you're buying a 40 gallon pot - to do BiaB?

That can't be right...

Cheers!

greater surface area of the pot bottom also increases heat transfer. It could be academic but you might see faster boil times (and great enery efficiency : )

That 3.5" diameter difference is 50% more surface area. You will see a difference in boil off rate.

I'm just interested in how much and where you got that 40gal kettle from.

thanks guys.. it was actually a stainless tank of something back in it's "day". still a flat bottom. I got it from a guy who was in a brew club that no longer brews. they bought like a dozen of them and built them for the members. but it's heavy walled compared to traditional pots. 19" by just over 30" tall, so actually 39 gallons and change. had a ball valve welded in right at the bottom all ready. very low compared to traditional. just a little tip of the pot and I got everything out buy maybe a cups worth with no dip tubes or anything. came with a lid as well... $80 bucks on craigslist... my buddy had close to $600 with his blichmann with a false bottom added. so when I came across this I jumped on it. just added one of bobby M's sight glasses. I'm in the process of making a rolling platform with a banjo burner with a upper bar/roller/winch system to pull the grain bag. my first batch was a 10 gallon batch of chocolate stout that had 32lbs of grain. took us both to get the bag out since the pot was up to our chests.