Steam Injected Mash

[vlbaby]

hi guys,
I have been experimenting lately with steam to control mash temperature but have had little success. At best I have been able to raise the temperature of 25L water by about 1 deg/ 3 minutes. I was hoping for a faster increase than this if i am to use this in stepped mashes. I have been using a pressure cooker fired up with a lpg burner, and connected to the mash tun manifold via a silicon hose. Maybe i am not doing it quite right.
Has onyone else used this system with success?

thanks


vlbaby.
View attachment 2324

Photo edited by Hoops 16/4/05 4:43pm

 

[Hoops]

Are you stirring the mash as you're injecting the steam?

 

[vlbaby]

i havent given it a go on the mash yet, just water at the moment to get a feel if its going to work, but yes i have tried stirring it.

 

[kungy]

Thats a sweet looking mash tun. Do you think you could post some specs of it and some more pictures.

Will

 

[berto]

At a guess id say the problem is that you dont have enough steam to do the trick. The actual volume of water in there is nowherenear that of a liquid and as such you wont be transferring as much energy up into the mash tun. With everything you have set up, why not get a bilge pump to pump thewater through either a heatexchange in the mash tun, or have a pickup intheir above your grain bed and continually rotate the water in your mash tun through your kettle

 

[vlbaby]

i'm thinking you might be right berto. Only thing with a RIMS setup is i dont think stepped mashes are possible. or maybe i'm wrong. besides i would need a pump also which i dont have yet.


kungy, the mash tun is just a keg wrapped in foam insulation (foam matress from rays outdoors) and cladded with some wood i bought from bunnings. Its a work still in progress, but so far it hold temperature much better than the esky with much more capacity

 

[Guest Lurker]

The actual volume of water in there is nowherenear that of a liquid and as such you wont be transferring as much energy up into the mash tun.

[post="54770"][/post]​

Dont forget that the energy is not in the temperature of the steam, its in the molecules of steam themselves which you get back when it condenses to water.

What heating rate do you need, say 2 degrees per minute to do steps?

It takes 4.2kJ of energy to raise 1 kg of water 1 degree.
To raise 25 kg 2 degrees needs 210 kJ
At 100% efficiency you need to deliver 210kJ into the tun in that minute.
The steam itself should be pretty efficient, but taking account of heat loss from the tun lets say 70% efficient, so you actually need to deliver 300 kJ.

The latent heat of steam is 2260 kJ/kg. Thats a big number which is why you can transfer a lot of energy using a small amount of water.
So you need to deliver 0.13 kg of steam to the tun in that minute.

So unless your burner can turn 130 ml of water inside the pressure cooker into steam in 1 minute you dont have a big enough energy source.

You could try an experiment where you bring the pressure cooker to pressure, weigh it, deliver steam to the tun for say 20 mins, weigh it again, and work out how much water has been lost and hence what your rate of steam generation is. Then you can work out if you have a problem with the rate of steam generation or with efficiency in the transfer.

Edit: Just to put it in perspective. Delivering 300 kJ in 1 minute is 5kJ/s = 5kW as a power rating. So lifting 25 kg of water by 2 degrees per minute is a reasonably big ask, if you had an electric element it would need to be 5kW, which is a fair size, so maybe that LPG burner is a bit small.

 

[Hoops]

vlbaby

Good job with the mash tun, I really like the look of it.
(Helps hide what's inside too h34r: )

Hoops

 

[vlbaby]

GL,
I'm thinking what your saying sounds true. Actually i was thinking that even if i had put the lpg burner directly under the mash tun and heated it, there's no way it could heat that water in that much time. I might try some experiments with weighing the pressure cooker like you suggested. But i think its going to show up the burner as the source. I went and checked, it is only 8000 BTU. A quick check on the net says that equals about 1.8kw . I could try it with my mongolian burner as it hits 130000 BTU.

I think its time to go back to the drawing board in any case.

vlbaby.

 

[ausdb]

hi guys,
I have been experimenting lately with steam to control mash temperature but have had little success. At best I have been able to raise the temperature of 25L water by about 1 deg/ 3 minutes. I was hoping for a faster increase than this if i am to use this in stepped mashes. I have been using a pressure cooker fired up with a lpg burner, and connected to the mash tun manifold via a silicon hose. Maybe i am not doing it quite right.
Has onyone else used this system with success?

Hi Vl Baby

I have used steam for step mashes in an esky twice now. My setup is not as flash as yours, I have a pressure cooker with a bulkhead fitting attached to it thats connected to a piece of insulated copper tube which runs into a an 'L' shaped steam injector/distributor that sits in the bottom of the tun.

On a 25L batch it took me about 23 minutes to go from 50C to 67C as GL says its related to the amount of heat you can apply to your steam generator. I usually leave it sitting in one place for a few minutes, then move it around and give the goods a stir withthe mash paddle every so often. Its amazing to watch as you can see when the mash is starting to convert it goes from that porridgy look to clearing and worty looking (highly technical terms here!) right before your very eyes.

At present I have a piece of 1/4" copper as my steam delivery tube and a very small opening in the bulkhead fitting of my pressure cooker. I am looking to change this to a fitting with a larger ID to get more steam into the mash as when I have the presure cooker on full noise and the valve open the relief valve still moves slightly meaning I am builiding up more pressure that I can get rid of in the cooker.

BTW how have you connected up to your pressure cooker? I have an old hawkins on and have drilled an extra hole in the lid for the setam fitting, that way I still have the factory weight in place (maintains 15psi for sterlising) and the factory relief valve.

I am also toying with the idea of trying to use steam to drive a HERMS arrangement, all I need ot do is build another small tube in tube heat exchanger similar to my counterflow chiller. I was wondering about trying it with the counterflow itself the other day.

I will look and see if I have any steam mach process pics and post them tonight

Cheers

Ausdb

 

[jayse]

Hi steam heaters.

I don't have anything to add re the steam issue but heres a artcile by someone who seems to have a good handle on why you can't properly do step mashes unless your steps are almost instant like that of using boiling water infusions or decoctions.
http://sdcollins.home.mindspring.com/HERMS.html

It is more of a herms article but the point about doing step mashes with almost instant temp changes i think makes great sense.

Anyway have a read and either take in on board or not eitherway have fun and lets us know your thoughts.

My take on it would be the steam could be used for temp control and a step to mash out nicely but doing a multi step mash iam not so sure.

Would be really cool to see one of you build a steam jacket on the mash tun for insulation and temp control, that'll be one for the beer porn forum. :super:


Jayse

 

[dicko]

Hi Guys,
With all that energy needed to generate steam I feel it may be easier just to have a tank of water, say 10ltrs, fit a herms coil, and circulate the wort through the coil while the water in the tank is heated to the correct temp to suit the step up in mash temperature.
I use a Herms which is currently in my HLT and it works well but I intend to build a separate tank for it so as not to interfere with the volume and temp of water in my HLT.
By having the herms coil in a separate tank I only need to maintain the exact volume of water in the HLT for the entire brew and not have to worry about keeping the herms coil covered with water or, having the water too hot for mash out / sparging etc.
The above is only my opinion and I would like to see a successful steam injection system and wish you well.
BTW, I lose 10 deg c of heat in my current herms system. That is, say to achieve a mash out temp of 76 deg c the water that heats the herms coil needs to be 86 deg c in my current set up.
Cheers