Adjusting for boil off/kettle size

I bought a 10 gallon kettle for my 5 gallon all grain brews. I did some volume experiments tonight with water and found that I need about 2 gallons to reach the bottom of the ball valve, which makes me think I will need about 8 gallons at the start of boil for a 5 gallon batch. Do I need to adjust my grain bill for starting with 8 gallons or can I just carry on as usual?

You're not going to just leave that wort in the bottom of the kettle are you?
I'm assuming you're talking about the boil kettle... you can either simply tip the kettle to get all the wort out, or add a dip tube. Either way, you are going to want to get all the wort out, and not just make a bigger batch to account for the loss.

To answer your question of batch size, you would need to add more grain if you're making a bigger batch.

Did you boil the water for an hour to find your boil off rate?

Wouldn't I pick up a bunch of trub if I tipped the kettle?

I did not boil the water but that is a good idea.

Helloworld said:

Wouldn't I pick up a bunch of trub if I tipped the kettle?

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Not if you tip it carefully and only take the clean wort after chilling and whirlpool.

Helloworld said:

I did not boil the water but that is a good idea.

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It's pretty important that you know what your boil off rate is.

Some people say ferment it all.
I do 6 gallon batches, and tend to leave about 1/2 to 1 gallon behind. People say I'm crazing for leaving wort behind, but 2 gallons? That IS crazy.
The bottom line, you need to calculate accurately all of your losses and either enter those into a calculator like Beersmith, or do it manually.
If you have 1 gallon of trub loss, and 1/2 gallon of fermenter loss, you'll need to brew 6-1/2 gallons to get 5 gallons into bottles or keg.
In order to scale 6-1/2 gallons from a 5 gallon recipe, it's easiest to use a brewing calculator... hops don't scale the same as grains.

Oops, double post

Helloworld said:

Wouldn't I pick up a bunch of trub if I tipped the kettle?

I did not boil the water but that is a good idea.

Click to expand...

Put in a 90° dip tube that almost touches the bottom and you'll drain most of your wort. If you need to tip you'll still get most w/o trub.


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Another vote for the dip tube. I use a hose barb elbow

Helloworld said:

Wouldn't I pick up a bunch of trub if I tipped the kettle?

I did not boil the water but that is a good idea.

Click to expand...

You might. So what? People have tried making beer without the trub and beer with all the trub and the major difference they see is that with trub they end up with more beer because they get all the wort instead of leaving some behind in the trub. They report that they can't taste any difference and their beers clear just the same.

govner1 said:

Put in a 90° dip tube that almost touches the bottom and you'll drain most of your wort. If you need to tip you'll still get most w/o trub.

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I actually found an older thread here that mentioned the same thing and it looked like a great idea; I'm going to head the hardware store after work today.

just make sure that you use a hose on the downstream side of the valve that is at least below the bottom of the pot. it takes a siphon to get it to go below the level of the valve. I've got a short 2' piece of hose that goes from my HLT to my mash tun that allows the HLT to drain almost all of the water out.

Gunfighter04 said:

just make sure that you use a hose on the downstream side of the valve that is at least below the bottom of the pot. it takes a siphon to get it to go below the level of the valve. I've got a short 2' piece of hose that goes from my HLT to my mash tun that allows the HLT to drain almost all of the water out.

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This is exactly what I was going to say. Can't say enough about using a hose on the downstream side of the valve that goes below the kettle bottom.

Mark