Full boil question

[NevermoreBrew]

So i just bought a bigger pot that allows me to do a full boil instead of a partial boil. What should my initial volume of water be for a 5 gallon batch? I use hopville to create my recipes so what should I adjust the boil volume to in the calculator? Will it make any difference in my ingredients as in should I alter my ingredients since my boil volume is higher than i typically do? Thanks

 

[krazydave]

Depends on the pot, the wider the opening, the more you'll boil off.
For my 80qt pot which has a huge opening, I lose about 1.75gal per hour. So I have to start with 7gal to hit 5.25 at the end.
Assuming yours isn't as big as 80qt though, you should be safe with 6.5 gallons pre-boil.
If you need more, you can always add more boiled and cooled water to your fermenter.

Edit: and no, ingredients should remain the same. You just boil more water off...

 

[NevermoreBrew]

its a 15 gal pot so i would probably go between 6.5 and 7. If i end up with too much water should i just have the hops in a strainer bag so i can remove them after the boil time and continue to boil down until i get my target volume?

 

[krazydave]

Doing that would still bitter the hop characteristics that are left once you take them out.
I would check it at 30 min and see where its at. At 30 min you should be half boiled off, so you'll have an idea of if you'll need to add more water later or boil it longer.
I usually shoot for the lower number and have the boiled and cooled water on the ready. After a batch or two, you'll know how much to start with the next time, and eventually not need the cooled water on the ready.

 

[Kahuna]

Evaporation rate will definitely vary with the shape of the pot, the intensity of the boil, the airflow around pot, and the relative humidity that day.

The only way to know what to expect is to try it out on your system a few times. So pick a volume between 6.5 and 7 and take notes. You'll have it dialed in, in no time.

 

[NevermoreBrew]

Would it be worth my time to put 6 gallons of water in my pot and boil it and see what my evaporation rate and keep track of what setting my burner is on?

 

[krazydave]

If you have the time, it wouldn't hurt.
However, I think you'll be fine just going head-in and brewing.
My pot is also a 15gal pot, so it should be similar.
Start with 6.75gal and have some water handy, you'll be fine.

 

[Aristotle]

Edit: and no, ingredients should remain the same. You just boil more water off...

Correct me if I'm wrong but wouldn't the hop utilization be different, meaning he wouldn't need as much bittering hops. Roughly 10-15% less. I know its not a big deal but I would want to know if I was him.

 

[krazydave]

Correct, the hops would be affected by a longer boil, however it's not going to ruin the batch and I'm sure it would still be quite tasty.
That's why I suggest shooting for a little less and adding water later as opposed to a longer boil.

 

[Seven]

Are you brewing extract batches? If yes, I'd aim low with the initial water boil volume, say 6.2 gals for a 5-gal batch. Once you add extract syrups, etc., it will raise the volume considerably.

You can always add more water in the middle or at the end of the boil if needed to hit your target.

Also be aware that the kettle and wort expands by about 4-percent while boiling so if you're aiming for 5-gals you may want to stop boiling at the 5.5 gal point (just a rough estimate). Once the wort cools it will be very close to 5-gals in the kettle.

Last but not least... like the others said: full boils will increase hops utilization so reduce the bittering (60-mins) hops by 10 to 15 percent if you don't want the extra bittering that will come from doing full boils when using a recipe that was most likely designed for partial boils. Leave the flavoring and aroma hops the same.

Have fun!