Cost of the boil.

[Nottsbeer]

I can get a reasonable boil using just the 900W heater on my Klarstein Fullhorn by leaving a small gap with the lid.
Here's the picture so you can see what I mean.

Hi Jof, is it fine to boil like that? I've always done an open top boil after hearing about the need to let something escape (can't remember the name). Does having a small gap let whatever it is out, as well as reducing heat loss...thus a great idea? May do that tomorrow if I get my next brew on

 

[RoomWithABrew]

using a condenser on the lid I have it completely sealed. gentle boil, using about 26% power on 3000w element.
No problems with dms at all.

 

[Marcale]

This may be of interest to those wanting to reduce the cost of boil. I went Solar! Posted today.

Post in thread 'Induction Hobs'
Induction Hobs

 

[Agentgonzo]

Hi Jof, is it fine to boil like that? I've always done an open top boil after hearing about the need to let something escape (can't remember the name). Does having a small gap let whatever it is out, as well as reducing heat loss...thus a great idea? May do that tomorrow if I get my next brew on

Yes, it's fine to boil like that. The thing that needs to escape is Dimethyl sulphide (DMS). It can still escape in the gap left by the lid.

Having an partially covered kettle is basically like the commercial breweries where they are covered but with a chimney for gases/steam to escape.

Nothing wrong with an open top boil though

 

[Weizenberg]

I found that lid closed with a makeshift chimney does the job nicely.

Its great for interrupted, on-off-on schedules as well (as described by Prof. Narziß).

 

[Agentgonzo]

Your definition of 'makeshift' is very different to mine . That looks the business!

 

[Nottsbeer]

Yes, it's fine to boil like that. The thing that needs to escape is Dimethyl sulphide (DMS). It can still escape in the gap left by the lid.

Having an partially covered kettle is basically like the commercial breweries where they are covered but with a chimney for gases/steam to escape.

Nothing wrong with an open top boil though

My boiler lid has a small hole in it, maybe 1cm diam. Do you think that would be fine with the lid fully on, or maybe not big enough?

 

[Agentgonzo]

From a chemistry standpoint even a small 1cm gap will let volatiles (like DMS) be driven off and they can escape through the hole. The lid will very quickly reach 100° or thereabouts, so the volatiles won't recondense on the lid. From my experience, I think you'll struggle to stop it boiling over (my grainfather has a ~3-4 cm hole in the lid and I have problems if I put it on fully during the boil)

However, with a small escape chimney/hole/gap, you may find that a head forms much faster on your boiling wort and you'll be at much greater risk of boilover. There are many things going on in the boil, and you won't get the same level of boil off as you would without a lid, which will affect your wort gravity.

There are probably other things happening as well.

 

[jof]

My boiler lid has a small hole in it, maybe 1cm diam. Do you think that would be fine with the lid fully on, or maybe not big enough?

My boiler also has a small hole, but that is not sufficient to let it boil at 900w. It will blow out of the hole if I were to shut the lid during the boil.
You will need to check your system to see what gap works best for you

 

[Weizenberg]

Your definition of 'makeshift' is very different to mine . That looks the business!

It'll be in action within the hour

 

[RoomWithABrew]

Putting an insulated cover on the lid if you have a chimney / condenser will help as well by keeping the lid hotter so less condensation on the lid and more encouragement to go up the chimney. You definitely need to factor in your reduced boil off in your calculations. My boil off is 650 ml an hour or a litre in 90 minutes.
So my pre and post boil gravity only changes about one gravity point during the boil for 25 litres to fermenter.

 

[foxy]

I think the point of removal of volatile's is being overlooked here. The volatile's are removed from the wort by the movement of the wort, IE rolling/vigorous movement. Any decent brewing book regularly states that. The steam is merely the conveyor, not the remover.

 

[RoomWithABrew]

I think the point of removal of volatile's is being overlooked here. The volatile's are removed from the wort by the movement of the wort, IE rolling/vigorous movement. Any decent brewing book regularly states that. The steam is merely the conveyor, not the remover.

Not sure about this theory.
Steam is water in it's gaseous phase.
DMS and other substances are dissolved in the water and as you say DMS is volatile. Boiling point 37.3 degrees celsius

Reading this article confirms you don't need to boil the wort at all to get rid of DMS but it's much more efficient to do so.

http://www.milkthefunk.com/wiki/Dimethyl_Sulfide
But if you want a good vigorous boil go for it, but it's not for the sake of the DMS removal.

 

[foxy]

Not sure about this theory.
Steam is water in it's gaseous phase.
DMS and other substances are dissolved in the water and as you say DMS is volatile. Boiling point 37.3 degrees celsius

Reading this article confirms you don't need to boil the wort at all to get rid of DMS but it's much more efficient to do so.

http://www.milkthefunk.com/wiki/Dimethyl_Sulfide
But if you want a good vigorous boil go for it, but it's not for the sake of the DMS removal.

Not a theory a fact, Timothy O'Rourke is a UK Master Brewer, Charlie Bamforth mentions the same thing as does Milk the Funk in the link you posted.
As I have said before, I don't care how anyone else boils, I am thinking of the new brewer just starting out, set me back first 12 months of brewing taking in some of the information offered up on forums.

During the boil, the converted DMS is evaporated off due to its low boiling temperature of 37.3°C [1] and the convection currents of the boil. Unhomogenized boiling of the wort can be a cause of DMS (e.g. dead-spots where the wort doesn't mix throughout the boil kettle). Calculations have been proposed to determine if this is a problem for a given kettle (see reference) [13].

Though Scott Janish is a home brewer he does take the time to look up the scientific papers relevant to home brewers.

http://scottjanish.com/how-to-prevent-dms-in-beer/

 

[RoomWithABrew]

I read the article and note

"Therefore, a very vigorous boil is not necessary for boiling off DMS."

The DMS moves down its diffusion gradient, extrapolation of brewery scale boilers to homebrew scale is not discussed in the reference you point to.
The DMS is not conveyed on the steam it does its own thing related to the laws of physics.
It would occur on heating whether water / steam was present or not.
I agree brewers should ensure there wort is boiling well and for long enough and use other tactics to reduce late DMS production.
But clouds of steam are not necessary to remove DMS but getting the DMS hot is.
If the DMS was in oil and assuming it didn't react with the oil it could be heated above 100 C so DMS loss would be quicker without any steam at all. This rate would accelerate more if the Hot oil was agitated.

 

[foxy]

I read the article and note

"Therefore, a very vigorous boil is not necessary for boiling off DMS."

The DMS moves down its diffusion gradient, extrapolation of brewery scale boilers to homebrew scale is not discussed in the reference you point to.
The DMS is not conveyed on the steam it does its own thing related to the laws of physics.
It would occur on heating whether water / steam was present or not.
I agree brewers should ensure there wort is boiling well and for long enough and use other tactics to reduce late DMS production.
But clouds of steam are not necessary to remove DMS but getting the DMS hot is.
If the DMS was in oil and assuming it didn't react with the oil it could be heated above 100 C so DMS loss would be quicker without any steam at all. This rate would accelerate more if the Hot oil was agitated.

As it is with agitation of hot wort! Don't cherry pick articles, take in what the experts say.

 

[RoomWithABrew]

Still don't see the experts saying steam is the conveyor of DMS except the learned @foxy.
Thank you for interpretation most valuable.

 

[foxy]

Still don't see the experts saying steam is the conveyor of DMS except the learned @foxy.
Thank you for interpretation most valuable.

Then you are reading the wrong articles. Are you reading Marshall Schott blogs? How else do you think DMS is removed during the boil? It is the agitation which removes the DMS and the steam which carries it away.
Do yourself a favour and watch this pod cast.

 

[Agentgonzo]

I read the article and note

"Therefore, a very vigorous boil is not necessary for boiling off DMS."

The DMS moves down its diffusion gradient, extrapolation of brewery scale boilers to homebrew scale is not discussed in the reference you point to.
The DMS is not conveyed on the steam it does its own thing related to the laws of physics.
It would occur on heating whether water / steam was present or not.
I agree brewers should ensure there wort is boiling well and for long enough and use other tactics to reduce late DMS production.
But clouds of steam are not necessary to remove DMS but getting the DMS hot is.
If the DMS was in oil and assuming it didn't react with the oil it could be heated above 100 C so DMS loss would be quicker without any steam at all. This rate would accelerate more if the Hot oil was agitated.

A good, simple (and correct!) description of the chemistry/physics that happens during the boiling of solutions (like wort) - easily understandable by beginners and advanced brewers. Thank you @RoomWithABrew

 

[foxy]

A good, simple (and correct!) description of the chemistry/physics that happens during the boiling of solutions (like wort) - easily understandable by beginners and advanced brewers. Thank you @RoomWithABrew

A classic example for new brewers to do the research and come up with their own conclusions.
'Beware of false knowledge, it is more dangerous than ignorance'.