Evapouration Rate With A 50l Keg

[razz]

You guys make me feel like im doing something wrong I lose about 9%

I bring the brew to the boil with my nasa at full power then I take it back to almost off and the brew stays at a gentle rolling boil.

I think in order to lose 15% like some of you I would have to be boiling the shit out of it.

[post="119842"][/post]​

G'day BB. I have been doing the same as you but, as the boil proceeds (last 45 mins) I gradually turn the reg back up slowly. This gives me that extra evaporation you are looking for.

John

 

[BennyBrewster]

Yeh Im using a converted keg with about 50% cut out of the top and I also have a s/s lid that sits resting diagonally on the keg handle.

Any disadvantage to not losing so much ?

 

[warrenlw63]

That's how I used to do it and the beers tasted just as good then as they do now.

Warren -

 

[cubbie]

Around 13% from my Keg and rambo burner. I prob have around a 25cm diameter hole cut in the top.

Start with the burner on high for the first 10-15min and then adjust back, maintaining a good rolling boil.

 

[sah]

I did my first boil (brew) with the nasa today. This is what happened:

- 32L of water in keg.
- 30 minutes to reach boil.
- addition of 4.5kg of LME.
- rolling boil for 60 mins.
- 25L out + approx 3L to trub = 28L after boil

Does anyone know what the volume (in L) of 1kg of LME is so I can calculate the boil off rate?

Cheers
Scott

 

[razz]

G'day SAH. I don't suppose that LME was a liquid ? If so just fill the container with water and measure, if not then you could have immersed the plastic bag of malt powder in a bucket of water and measured how much water it displaced.

 

[goatherder]

Does anyone know what the volume (in L) of 1kg of LME is so I can calculate the boil off rate?

Cheers
Scott

[post="119882"][/post]​

Measure the tin and do a volume calc on it - pi * r^2 * h . If r and h are in metres, then the answer will be in cubic metres - multiply by 1000 to get litres.

 

[sah]

Razz, LME is an acronym for liquid malt extract.

Razz & Goatherder, Thanks for the comments about how to work out or calculate the volume of the LME. This I could have done but didn't think to before throwing the containers in the bin. I'm not about to fish 'em out.

Bindi, this was my first no chill too. Too easy

If I guess that the volume of the 4.5kg of LME is about 2L my boil-off rate is:

1 - 28/34 = 17.6%

I do have about a large a hole in the top of the keg as there could be though.

Scott

 

[Ducatiboy stu]

I start with a preboil vol of 29ltrs, and end up with a chilled (ooooohhhh..did i mention that word) volume of 22ltrs, taking into account the 450mls due to shrinkage and 500mls hot break, gives me an evap of 6 ltrs for 60 mins, with a 300mm opening and good rolling boil.

My fermenters seem to evaporate brew, but this may be due to consatnt sampling to ensure the brew is good... h34r:

 

[sah]

I start with a preboil vol of 29ltrs, and end up with a chilled (ooooohhhh..did i mention that word) volume of 22ltrs, taking into account the 450mls due to shrinkage and 500mls hot break, gives me an evap of 6 ltrs for 60 mins, with a 300mm opening and good rolling boil.

[post="119906"][/post]​

Congrats Ducatiboy, you've got the record so far at 20%

Scott

 

[browndog]

Stu, isn't 4% the general rule for shrinkage due to cooling? that would give you a loss of a bit over 1L for 29L and what is this 500ml loss to hot break? How does that work?
To get 21L in the fermenter I need 30L in the kettle allowing for 4.5L/60min boil off, 1L shrinkage and 3.5L loss to trub.

cheers

Browndog

 

[sosman]

My typical boil off is 10 litres for a 60-75 minute boil:

I skim just as the wort is coming to the boil if for no other reason than I reckon I can boil harder with less risk of boilover once the blanket of foaming scum is removed.

 

[Tony]

I use a rambo burner. takes 10 to 15 min to get 58 to 60 liters rolling in the kettle

Plenty of heat from a low pressure burner

mt old 3 ringer only gave me 2.5L/hr

cheers

 

[Ducatiboy stu]

The 500 mL hot break is what is caught in my filter bag when i empty it into the ferm

I set my volumes for a pre boil of 29 ltrs, and get 22 ltrs in the ferm....thats my system..and it is consistant

 

[Hogan]

Plus if you've cut the standard hole in your keg with an angle grinder there's still enough of the keg top to catch a little bit of the condensation and have it drip back in to the boil.

Warren -

Trent.

When I did 40 litre batches in a 50 litre keg I would boil with the lid partially over the opening to deliberately reduce the evaporation rate and turn down the burner. While it's not deemed a proper practice the resultant beers were fine, if not very good. :beerbang:

I initially obsessed about the condensation off the lid dropping back into the boil. Then I thought bugger it, it's only really water. Anything that's deemed volatile would most likely channel out into the outside air. :unsure:

Also worth noting that your efficiency seems to automatically improve with larger batches. Why? No bloody idea. :blink:

Warren -

Read somewhere that letting the evaporation drip back into the kettle is a bad thing. I have a 50lt keg that has an old mircrowave plate that fully covers the top rim when I get to rolling boil.

Still plenty of room where the handle cut-outs are on the side to let out the steam but some does condense on the bottom of the plate and drip back into the boil. What effect would this have, if any?

My evap rate for a 90 minute boil of 30 lts is about 7 lts.


Edit: Additional Warren quote - exactly what I mean.



Cheers, Hogan.

 

[Steve]

I lost 7 litres to evaporation on Saturday with my 50litre keg and 3 ring burner...I was a bit worried until I found this thread. One question I do have though is when you're only boiling say 25 litres how does everyone manage to see the surface of the wort down there in the depths of the keg with all the steam billowing out. I had to stand there with a ss pot lid wafting madly with my head in the top of the keg to be able to see the bottom, and even then if was a fleeting glance to notice that it had actually come to the boil? A torch maybe?
Cheers
Steve

 

[devo]

I have about 52ltr pre boil in my 70ltr pot and end up with with about 42ltr into the fermenter after 90min boil with a standard 3 ring burner.