Stand Alone Heat Exchanger

[AUHEAMIC]

I am about to build a stand alone heat exchanger to upgrade to a HERMS system. Im fine with building it but have a question regarding using it.

When I recirculate through the heat exchanger periodically to bump up the mash temp the grain bed will set (?). Should I stir it up again after each recirculation or will the wort passing through the grain be good enough.

I hope its the later so I can set my return manifold at the correct height (just under the water level), seal up the mash tun and not open it again until I am ready to (fly) sparge.

Thanks in advance
Peels

 

[domonsura]

I reckon that you would be OK just leaving it, and then do a stir before you start sparging.

 

[gnewell]

I reckon that you would be OK just leaving it, and then do a stir before you start sparging.

Mate of mine has a HERMS.
He is constantly recirculating. To change the temperature of the mash, he just bumps the temperature in his 'heat exchanger' and up goes the mash temp. Too easy. His return is just below the liquid level as you indicated.
I don't rate the HERMS system myself though. Extra complexity and cost for arguably minimal gain. Happy to explain why if interested.

 

[Doogiechap]

Hey Peels,
I pretty much recirc for the full 90 mins with my sparge /return at the waterline. My mash tun is a 38l Gatorade tub so I pretty much seal the lid and keep an eye on the mash temp (which will be getting more stable once I incorperate my mashmaster controller into my heat exchanger). Modifying mash temps via the herms is a very slow process so 'stepped' mashes are difficult to achieve via the heat exchanger.
Cheers
Doug

 

[razz]

I am about to build a stand alone heat exchanger to upgrade to a HERMS system. Im fine with building it but have a question regarding using it.

When I recirculate through the heat exchanger periodically to bump up the mash temp the grain bed will set (?). Should I stir it up again after each recirculation or will the wort passing through the grain be good enough.

I hope its the later so I can set my return manifold at the correct height (just under the water level), seal up the mash tun and not open it again until I am ready to (fly) sparge.

Thanks in advance
Peels

Go the later peels. Iv'e had mine for a couple of years now and I don't even recirculate until I'm ready to mash out. Recirc for about 15 minutes for the mash out is enough to get a good filtered bed going. The fluid level will drop initially when you start to recirc but it should not set.

 

[AUHEAMIC]

Geoff
The extra complexity for me is a bonus. Being an ex fitter and turner I love making equipment almost as much as I love brewing and drinking beer. I would however like to hear your thoughts on the minimal gain issue.

Doogiechap
Have you noticed any change in efficiency, up or down, by recirculating for the full 90mins?

Razz
What is the volume of water in you heat exchanger?

 

[razz]

Its 40 lts peels, it's my hlt.

 

[AUHEAMIC]

Its 40 lts peels, it's my hlt.

I was thinking about putting a coil in the HLT but I dont know how this works. This is what I do now. Heat 45ltrs in the HLT to strike temp, run 25ltrs into the mash tun and add grain. I then refill the HLT to 45ltrs and heat it up to sparge temp (I fly sparge). It takes a good 45 minutes to get the temp back up so I couldnt recirculate until then.

I hope this makes sense.

 

[razz]

Peels that's almost the same as what I do. But, I heat my mash water and fill the mashtun the night before and then refill the hlt and boil, set the thermostat for 80 degrees and leave overnight. In the morning I recirculate the mash liqour to get it to my strike temp and after dough in the hlt is set to go for spargeing.

 

[Doogiechap]

Peels I can't comment about efficency variation as I cracked my AG cherry on my Herms setup 7 brews ago, that said my comments are not exactly backed up by a wealth of experence. It was however recommended by a very experienced brewer with a herms setup that I recirc from the start so that's what I followed.... I started off with my Herms heat exchanger as my HLT but rapidly grew tired of the lack of flexability so have a separate HLT which I scored form the Tip before it hit the dirt from someones car being a 40 liter Urn with a 3Kw element. :super: .

 

[razz]

Doogie, that's very interesting about the brewers comments on recirculating, I used to recirc for about 45 mins of the 90 min mash but now I just don't bother. I get the same efficiency, but more importantly the liqour running into the kettle is always clear.

 

[AUHEAMIC]

Thanks for the info fellas. It gives me a starting point. Just (hopefully) one more question. I have a 12ltr stock pot I was going to insulate and use for my heat exchanger. Do you think 12ltrs will have enough thermal mass?

 

[Doogiechap]

Thanks for the info fellas. It gives me a starting point. Just (hopefully) one more question. I have a 12ltr stock pot I was going to insulate and use for my heat exchanger. Do you think 12ltrs will have enough thermal mass?

Peels it probably depends on what you wanted to do with your setup and how much you would like it to 'correct' temprature variations. My assumption (I am happy to be corrected) is that the water's thermal mass obviously plays a part in changing the mash temp but it predominantly is a 'medium' for transferring the heat from the element/ burner into the copper coil of Wort imersed in it so I think the heating capacity plays a larger role in the process than the volume of liquid. If you are seeking minor corrections/ maintaining mash temp then that sounds fine but if you were looking to use the Herms for raising the temp to 75 mashout levels then a larger thermal mass would be needed. There are a couple of rocket science type bloke's on the forum who get a kick out of thermal mass calculations (can't remember you you are sorry !) so they might be able to weigh into the topic with more authority. Insulation is definately a good thing (not that I have got around to that yet......

Doogie, that's very interesting about the brewers comments on recirculating, I used to recirc for about 45 mins of the 90 min mash but now I just don't bother. I get the same efficiency, but more importantly the liqour running into the kettle is always clear.

Razz that sounds very interesting, my efficencies are all over the shop with the newbie factor, going from fly to batch sparging, incorporationg my homemade crusher blah blah so if I nail my strike temp I might hold off on the recirc and see what sort of outcome I get.
Cheers
Doug

 

[gnewell]

Geoff
The extra complexity for me is a bonus. Being an ex fitter and turner I love making equipment almost as much as I love brewing and drinking beer. I would however like to hear your thoughts on the minimal gain issue.

Doogiechap
Have you noticed any change in efficiency, up or down, by recirculating for the full 90mins?

Razz
What is the volume of water in you heat exchanger?

Hi Peels,
Here are some of my points. Caveat- As with most brewers my opinions are just that, opinions:
1) From my discussions with brewers and craftbrewers, almost all of the commercial beers are produced without a recirculation aspect throughout the mash. Vorlaufing is very important at the end of the mash which helps to clear any grain particles from the lauter and clear the run off a little.
2) The big benefit of a HERMS is supposed to be the clarity of the runoff. Again this is often debated. A slightly hazy wort means a more protinaceous wort. When the kettle finings are added, they allegedly cause the break to clump together better with a more protinaceous wort.
3) A lot of HERMS brewers naturally do fly sparging. Unless you are constantly monitoring the PH of your wort when you are sparging you are liable to extract tannins from your grain. So you have the complexity of that.
4) You have more equipment to clean after your brew day. I hate cleaning so I like to keep it simple.

My setup is gravity fed and I batch sparge. If I need to do a step-mash, I use an infusion heater which I plunge into the mash. Most step-mashes seem to be redundant with the fully-modified malts we all use these days.

I can see two benefits with the HERMS system:
1) The vorlaufing at the end of the mash could be automated through the pump. (don't need the heat exchanger though).
2) The improved efficiencies due to fly sparging would save you a few pennies on each brew.

Any way, that's my 2 cents worth.

Geoff.

 

[AUHEAMIC]

I have a 50ltr stainless steel mash tun which is insulated with 1 layer of sizilation, 2 layers of 10mm thick foam camping mat and then duct tape wrapped around and around the whole lot so it is water proof . The bottom also has two layers of camping mat glued to it. The lid has one layer of camping mat. When I put the lid on I fill up the cavity (from the lid to the top of the rim, you know what I mean) with a towel and place a sheet of chip board on the top.

I still loose 5-6 degrees over an hour long mash!!!

I think part of the heat loss problem is that I (was told to) stir the mash every 15mins (to help enzyme action).

I want to be able to hold my mash temp constant over the whole mash time and I want to mash out.

After all your advice I am now thinking of putting the coil in my HLT. As I said above I fill my HLT to 45ltrs and 25-30ltrs goes into the mash tun, then top the HLT back up to 45ltrs and heat (which takes about 45mins) to (fly) sparge temp.

I could add a couple of degrees to the strike temp and wait until the HTL is hot enough to recirculate and then dough in. It would only add 45mins to my brew day which for me is a bonus (out in the shed away from ???)

Does this sound OK?

 

[alowen474]

I have a 50ltr stainless steel mash tun which is insulated with 1 layer of sizilation, 2 layers of 10mm thick foam camping mat and then duct tape wrapped around and around the whole lot so it is water proof . The bottom also has two layers of camping mat glued to it. The lid has one layer of camping mat. When I put the lid on I fill up the cavity (from the lid to the top of the rim, you know what I mean) with a towel and place a sheet of chip board on the top.

I still loose 5-6 degrees over an hour long mash!!!

I think part of the heat loss problem is that I (was told to) stir the mash every 15mins (to help enzyme action).

I want to be able to hold my mash temp constant over the whole mash time and I want to mash out.

After all your advice I am now thinking of putting the coil in my HLT. As I said above I fill my HLT to 45ltrs and 25-30ltrs goes into the mash tun, then top the HLT back up to 45ltrs and heat (which takes about 45mins) to (fly) sparge temp.

I could add a couple of degrees to the strike temp and wait until the HTL is hot enough to recirculate and then dough in. It would only add 45mins to my brew day which for me is a bonus (out in the shed away from ???)

Does this sound OK?

Peels,
I have a 50L stainlesss keg mash tun with a thermometer sticking out the side. When I mash I just sit an inch thick bit of polystyrene over the top cut to fit and wrap it in a one inch bit of foam.
This only loses about one degree while mashing.
You may just be getting inconsistent reads with your thermometer.
Cheers

 

[Doogiechap]

I have a 50ltr stainless steel mash tun which is insulated with 1 layer of sizilation, 2 layers of 10mm thick foam camping mat and then duct tape wrapped around and around the whole lot so it is water proof . The bottom also has two layers of camping mat glued to it. The lid has one layer of camping mat. When I put the lid on I fill up the cavity (from the lid to the top of the rim, you know what I mean) with a towel and place a sheet of chip board on the top.

I still loose 5-6 degrees over an hour long mash!!!

I think part of the heat loss problem is that I (was told to) stir the mash every 15mins (to help enzyme action).

I want to be able to hold my mash temp constant over the whole mash time and I want to "mash out".

After "all" your advice I am now thinking of putting the coil in my HLT. As I said above I fill my HLT to 45ltrs and 25-30ltrs goes into the mash tun, then top the HLT back up to 45ltrs and heat (which takes about 45mins) to (fly) sparge temp.

I could add a couple of degrees to the strike temp and wait until the HTL is hot enough to recirculate and then dough in. It would only add 45mins to my brew day which for me is a bonus (out in the shed away from ???)

Does this sound OK?

G'day again Peels,
Yes the dough in process sounds feasible if time is your friend (it's not for me hence the separate heat exchange). I should have posted this earlier but here is a great link on Herms limitations, it gives a good rundown for you particularly as you fly sparge.
Cheers
Doug
PS I must say that whilst there is extra cleaning with the Herms sysyem, all I do is connect it in series with my CFC, mash tun and sparge arm and pump nappisan through the whole lot on a continous cycle for an hour or so, flush with tap water then repeat with no rinse sanitiser. Minimal fuss .

 

[AUHEAMIC]

Well thanks everyone for all your input. I have built my heat exchanger and given it a test run with plain water and it works as I wanted it to. It will hold the water temp within 1 degree and takes 15 minutes to ramp the temp from 65 to 75 degrees. The big test will be next weekend when I put it to use for a brew.

Just thought I would post a couple of pics of the near finished product. I still have to mount my Mashmaster controller in a box.

 

[Sammus]

Heres my HERMS - a 5lt insulated bucket and kettle element. I recirc constantly, hold temps perfectly, never stir, and step 65-75 in 10-15min. Not much good when I get 80-85% eff into the kettle, and about 58% into the fermenter. Don't know where the loss is, maybe im underestimating my loss to trub/chiller/hoses. I was getting that eff before I used the HERMS so I don't reckon its the problem anyway

I just got a 8lt staino pot which I think I'll make my herms out of now, with connectors through the wall. If you look at my current setup, you can see its pretty annoying whenever I want to do anything to it. Id much prefer a self draining coil and be able to remove the lid as I please.

Oh, and my wort is never very clear...dunno whats going on there.

 

[AUHEAMIC]

Thought I would give you all an update. Since last post I have mounted a Mashmaster control and insulated all the hoses. I have used it twice now and I must say it works really well.

On my last brew (Irish Red Ale) I stuffed up my strike water temp. I was aiming for 68c and ended up with 64c. I had the heat exchanger set to 69c and after 6mins of recirculating I had the mash up to 67c which was close enough.

I also managed to perform a mash out with it. At the end of the mash I set the heat exchanger to 78c and after (about) 15mins the mash was at 75c.

Some specs:
8 Litre aluminium stock pot
2200 watt element
6 meters of 3/8 copper