First BIAB, question about using a 5 GAL kettle?

[BansheeRider]

I want to start all grain brewing but all I have is one 5 gal brew pot. With extracts I would do a partial boil (3.5 gal) and top off the fermenter with cool spring water. Can I do the same thing with an all grain BIAB setup? Or do I need to do full volume boils? I know full boils are preferred regardless but I just want to know if this is possible and still make great beer. Thanks!

 

[JeffD1]

Seems like it works. Check this out:
http://www.brews-bros.com/index.php?/topic/1980-all-grain-partial-boil/

 

[TopherM]

Yeah, you can do top off water with BIAB. You should start saving up for a 10-12 gallon pot, however. Hop utilization is better at full volume, and it's just a billion times more convenient.

I have the 44 QT Bayou Classic WITH a perferated basket that's awesomely convenient for BIAB, and it cost me $87.00 shipped.

 

[mb82]

You could top up but that is not the preferred way due to hop utilization. You could always brew smaller batches. I have a 6 gal kettle and use it for 3 gal batches.

 

[BansheeRider]

You could top up but that is not the preferred way due to hop utilization. You could always brew smaller batches. I have a 6 gal kettle and use it for 3 gal batches.

How is this any different than wort made from extract? Many people do partial boils and not worry about hop utilization. Is this more of a concern with AG?

 

[sublimefool311]

I'm in the same situation as you, OP. Here's what I do:

For 2.5 gallon batches, I do full boil. Aim for about 3.5 gallons at the start of the boil. This is pretty straight forward.

For 5 gallon batches < 1.050, I do a concentrated boil. I also aim for 3.5 gallons, but it doesn't matter as much because you'll be topping off anyway.

For 5 gallon batches > 1.050, you pretty much have to use some extract. This is really just a matter of not being able to fit all of the grain in the pot without it spilling out.

That being said, for the 2.5 gallon batches, I mash with the full volume of water. After mashing, I heat the water up to 170 F and let it sit at that temperature for about 15 mins. For the bigger 5 gallon grain bill, I have to sparge in a separate container. I heat the sparge water to 170 F and dump it into my fermenting bucket. Then I dunk the grain bag and let that sit for 15 minutes. After that, I combine that liquid with the wort in the kettle.

You can use the Simple BIAB calculator to get the necessary volumes. Just put the starting boil volume in the spot for finished beer and put a zero in for trub loss.

One more thing, if you are working with a 5 gallon recipe, plug that recipe into a recipe builder and make note of the IBU. When you scale down the boil, you need to add more hops to make up for the lower utilization.