Boil off rates

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Permalink Reply by James P on November 10, 2009 at 9:01am

Hi Toot, I would say your boil is too vigorous. I have a converted keg and a three ring burner, and once I get the boil on I turn off one or two of the rings to get that lazy rolling boil. My boil off is about 7~13% an hour.

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Permalink Reply by Toot on November 10, 2009 at 9:15am

Hmm true, will try that next time.

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Permalink Reply by jt on November 10, 2009 at 10:13am

What did you allow for shrinkage after the boil and for hop & trub ?
Your boil off rate may be less than the 42%

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Permalink Reply by Toot on November 10, 2009 at 10:35am

I think beersmith defaults at 4% shrinkage. which is about 1.4L. So brings the boil off rate down to 36%. Still real high.

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Permalink Reply by Reviled on November 10, 2009 at 10:22am

Definately sounds like youre cranking the burner too hard mate!

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Permalink Reply by Toot on November 10, 2009 at 10:36am

Yeah will crank it down for the next brew, gas bottle will last longer too.

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Permalink Reply by denimglen on November 10, 2009 at 5:06pm

Did you dump everything into the fermenter or did you leave some trub behind? Remember to account for this in your 'loss to trub and chiller' field.

I believe common is 4 - 6 L per hour with most kettles.

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Permalink Reply by Toot on November 10, 2009 at 9:33pm

Left the trub behind, usually get about 1-3 L with our kettle. Got about about 1 L this time.

Hey just another question about beersmith. Do you stop sparging when you reach the calculated boil volume? If so then will your losses to trub effect how much the boil volume will be?

ie If I Lose 4L to trub and chiller then does beersmith have you sparge 4L extra to account for it? Does that effect final wort concentration or does it account for it in the recipe.

If I'm aiming for 20L in the fermentor and have trub losses of 4L should I be doing a 24L brew (recipe wise) to allow for it is what I'm trying to say lol.

Clear as mud......

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Permalink Reply by jt on November 10, 2009 at 9:41pm

Brewing software makes it all so easy !

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Permalink Reply by denimglen on November 11, 2009 at 5:10am

I'm batch sparging and seem to have it pretty much dialed in, so I'm usually +- 500mL into the kettle.

Your batch size in beersmith is what's sitting in the carboy fermenting.

You were right the first time, beersmith calculates backwards from the batch size. You can see this when you go into your equipment settings and tick the 'calculate boil volume automatically'. So your batch size is 20L, you enter 4L loss to trub, 1L cooling loss, and 4L boil off and it will calculate you a boil volume of 29L. It then works out your mash/sparge with your lauter tun deadspace loss and grain absorbation to give you 29L into the kettle.

Hope that helps a little.

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Permalink Reply by sid on November 11, 2009 at 11:02pm

I loose around 8-10 litres in a 90 minute boil with the same set up you have, if I'm wanting a 30 litre finshed batch I start at around 40 litres.....................this is all boil in a bag.

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