Boil off Rate

Hey everyone

I am trying to perfect my all grain set up and tonight i am going to figure out my boil off rate. Everything i have read says just fill your boil kettle with a calculated amout of water, boil for 1 hr and do the math. However wouldn't calculating water boil off rate be different than wort boil off rate due to sugars and the viscosity of the wort?

Just trying to make the best beer possible.

There very well be a slight difference, though I've never noticed it. I suspect it's so small to be a useless measure. Sounds like you are on your way!

So i figured out that my boil off rate is 1.5 gallons per hour. So I figure for to end up with 5 gallons finished product I need to start my boil with 7.5 gallons. 1.5 gallons boil off plus .5 gallons left in kettle and .5 gallons in trub loss. Does that make sense

You've got it!

simcoe26 said:

So i figured out that my boil off rate is 1.5 gallons per hour. So I figure for to end up with 5 gallons finished product I need to start my boil with 7.5 gallons. 1.5 gallons boil off plus .5 gallons left in kettle and .5 gallons in trub loss. Does that make sense

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Don't forget grain absorption.

+1, don't forget grain absorbtion!

Also, you are going to lose about 0.2 gallons to contraction during cooldown.

Also, you don't need to lose 0.5 to "left in kettle." Pour all of that in the fermenter, it's good for yeast health!!

sfrisby said:

Don't forget grain absorption.

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simcoe26 said:

So i figured out that my boil off rate is 1.5 gallons per hour. So I figure for to end up with 5 gallons finished product I need to start my boil with 7.5 gallons. 1.5 gallons boil off plus .5 gallons left in kettle and .5 gallons in trub loss. Does that make sense

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Grain absorption accounted for

The left in kettle numbers are due to the fact that i use keggles and in my boil kettle my pick up tube is a side pick up and it leaves 46 ounces so even if i wanted to get it out for" yeast health" I would be quite the pain. Also wouldn't factoring in grain absorption be more about how much to mash and sparge with and less about what happens in the boil and after the boil

simcoe26 said:

Also wouldn't factoring in grain absorption be more about how much to mash and sparge with and less about what happens in the boil and after the boil

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That would be assuming, for some wacky reason, that you weren't boiling your grains.

Huh. Why would i boil grain, unless i am doing a deccotion Mash then my actual grain doesnt get above 170

bleme said:

That would be assuming, for some wacky reason, that you weren't boiling your grains.

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i don't boil them

simcoe26 said:

wouldn't factoring in grain absorption be more about how much to mash and sparge with and less about what happens in the boil and after the boil

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I brought it up in regards to his starting volume but was irrelevant as he pointed out he was referring to a starting boil volume, after the mash.