first biab - 7 gallon kettle

[gregfreemyer]

I want to do my first biab, but I'm confused by the water volume I need. I only add water once at the beginning right?

I've read people saying a 5 gallon batch with biab needs a 10 gallon kettle. My kettle is only 7 gallons, so can I only do a 3 1/2 gallon batch?

And should I start with 4 1/2 gallons assuming a one gallon boil off?

Why can't I start with 6 and let it boil down to 5?

Thanks
Greg

 

[Calder]

You can make whatever you can fit in the kettle. You can put 6 gallons in a 7 gallon kettle. If you boil too much off, you can always just add water to the fermenter to get back to the desired volume.

 

[TonyG]

Depending the amount of grain you are using, mash with something like 4 gallons and top it off to 5.5-6 gallons before you start your boil. Just be diligent about watching for boil overs and you will be good to go.

 

[gregfreemyer]

I've been doing more reading and I think the need for a bigger kettle is the mash, not the boil.

At least this first time I want to do a true biab - no sparge, no extract and top off only as needed.

I think with true biab, it's all done in one vessel - 60 min mash, lift bag full of grains, let drip for a while back into pot, top off as needed, boil

Did I skip a step if my goal is to do it "right"?

Back to water, do I have this right:

If I shoot for a 5 gallon batch, then I need about 8.5-9 lbs of grains for a wit bier. I think biab uses a minimum of 3 quarts per lb to mash, so I'll say 27 quarts or 6.75 gallons. No boil off during mash, but I should expect to lose 0.1 gal / lb of grain to absorption, so that leaves 5.85 gallons for the boil. I would top off to 6 gallons and start the boil.

There's no way my 7 gallon kettle can hold 6.75 gallons of water and 9 lbs of grain at the same time. Looks like I should scale it back to a 3.5 gallon batch in my 7 gallon kettle.

Then if I want to stick it out with biab, get a bigger kettle. (I saw a 20 gallon full setup at home depot yesterday for under $200. I think just a 10 gallon kettle was about $80 and I could use my existing propane burner.)

Greg

 

[jdonley]

I also BIAB and have a 7.7 kettle. I fill it to 5-5.5 gallons and I can fit 12-12.5 lbs of grain in there. The grain soaks up a lot of water during the mash. I squeeze as much wort out of the bag as I can and then make up for the lost wort with my sparge water. I usually add enough sparge water to get me to around 6 gallons in my brew pot if I'm doing a 60 minute boil

 

[Weezy]

I also BIAB and have a 7.7 kettle. I fill it to 5-5.5 gallons and I can fit 12-12.5 lbs of grain in there. The grain soaks up a lot of water during the mash. I squeeze as much wort out of the bag as I can and then make up for the lost wort with my sparge water. I usually add enough sparge water to get me to around 6 gallons in my brew pot if I'm doing a 60 minute boil

This is the trick here.

BIAB is traditionally full volume, all the water, added at the beginning. This includes enough water for the final batch size+boil off+water left stuck to the grain. If you can't fit all of that plus all the grain in your pot, you just want to plan for some sparge water from a second pot.

If you have another decent size pot, its easy to heat spare water in it and dunk the grain bag into that pot, stir, then pour the wort back into the main pot.

If don't have another big pot, you can just heat some spare water in a small pot and pour it over the grain bag.

 

[soccerdad]

I can do 5 gal batches in an 8 gallon kettle, but my grain bill is usually 12 pounds or less. A beer of 1055 or less is generally doable. If you get real good efficiency in the mash you can top off to make up for a greater than expected boil off .. or if you hit your gravity and you are at 4.6 gallons -- so what??

 

[MikePote]

I have 4 or 5 BIAB batches under my belt. I use two pots - an 8 gallon which is my boil kettle and sparge pot and a 7ish gallon which is my mash pot. I do 1.25 quarts of mash water per pound of grain like any AG brewer. At the end of the mash I lift the bag and let the grains drain into the pot, then put a colander on top of the pot and smash the bag with a potato masher. After smashing the bag it goes into the other pot which has whatever volume of 170 degree sparge water I need to get to a 6.5 gallon boil. I do a simple dunk sparge where I also smash the grains with a colander/potato masher to get everything out I can. I have gotten 75% efficiency doing this and it has been fairly simple. I boil 6.5 gallons in my 8 gallon pot. It is tight but so long as Im standing there to turn down the heat for the first boil over (hot break I think) I can boil aggressively without fear of boiling over.

Don't be afraid to do 6 gallons in your 7 gallon kettle. I am also a noob but at this time I have no desire to do AG with full equipment. Not sure where you will mash or boil but I mash inside my stove. I preheat the oven to 170 degrees (lowest setting) and turn the oven off before doughing in. When the grain is in the strike water I put it in the oven and so far it has maintained temp within 1 degree every time. Good luck.. Worst case scenario you screw something up but still make beer. Pretty good worst case.