Boil off rates

[Toot]

Currently having a few volume issues with our setup.

Did what was supposed to be a 25L brew last night, sparged to 34L, boiled for one hour and ended up with 20L in the fermentor.

Im using a 3-ring gas burner with a converted keg for a boiler.Is 34L to 20L in an hour a 42% per hour boiling rate? This seems pretty high. What sort of boil off rates do you guys get?

[James P]

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.

[Toot]

Hmm true, will try that next time.

[jt]

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

[Toot]

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

[Reviled]

Definately sounds like youre cranking the burner too hard mate!

[Toot]

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

[denimglen]

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.

[Toot]

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......

[jt]

Brewing software makes it all so easy !

[denimglen]

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.

[sid]

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.