DIY bath pasteurizer w/ tankless water heater

[Nat West]

There are many threads and some pictures of people's home-built pasteurizers but I've not seen any like this, other than Rich Anderson's, who gave me the idea. It holds 120 x 750ml bottles in rectangular milk crates. One batch is about 20 minutes in the water to 60 C. I can fill the bath in about 20 minutes using two ganged-together water heaters (my home's domestic water heater set to 122 F and the one below set to 185 F).

https://www.facebook.com/photo.php?v=403800036329985

I can provide more pictures if anyone would like but here is the setup.

• MacroBin 16 S. This is used in the wine industry quite widely, although the 24 is a more standard size. Rated to 190 degrees F or more. Buy the optional lid. $200?
• Semi-cheap bronze head pump. My particular model is Tellarini Pompe. The important thing is that it is rated to 190 degrees F. Handily, it has garden hose threads. $125
• CPVC flange, elbow, adapters, valve, etc bits. CPVC is rated for hot water, PVC and ABS is not. I got the schedule 80 thick wall stuff. ~$50
• Rinnai tankless water heater R94 LSI. Runs on natural gas or propane. You can get the smallest BTU water heater you can find but it needs to go to 185 degrees, and most don't. This one is a "commercial" unit, and needed an optional controller to raise the temp to 185 F. $150 (used on craigslist) plus $100 for controller.
• Water heater rubber hose, garden hose barb fittings. ~$40

Total: $635

Not included in the cost: black iron pipe to get from my gas meter to the water heater.

I have seen similar capacity pasteurizers for sale for $6700 using electric elements. Installation steps:

1. Drill a hole in the middle bottom of the MacroBin, insert the CPVC flange, sealing it down with silicone caulk (rated to 400 F). Bolt-through the flange with SS hardware.
2. Connect CPVC adapter, elbow, pipe and valve to get the "drain" to extend to the side of the bin. The bin has feet/runners built in which makes the piping easy to install. Fasten the pipe to the runner with some pipe hangers. End the CPVC pipe in a garden hose adapter.
3. Connect a short length of rubber hose from this bin drain outlet to the pump.
4. Connect the other side of the pump to the cold water in side of the tankless water heater.
5. Connect the third hose from the hot water out side of the tankless back to the bin. I just draped/hung the end into the bin, but you could get fancy with another fitting through the wall of the bin.

I still need to:

     6.  Install screens at the bin drain, after the drain valve/before the pump inlet and after the pump outlet/before the water heater inlet. The water heater has a small screen filter built-in.

Some notes: 

• Make the rubber hoses have female-female ends to ease attaching and detaching.
• The water heater has valves on the IN and OUT water ends with garden hose threads so no fittings are needed there.
• I'm "starving" the water heater on BTUs a little bit with a long 3/4" pipe run, but it uses so little gas in recirculation that it's okay.
• Carefully measure the depth under the MacroBin before you commit to whatever drain fittings you're going to use. You have a limited amount of space under the bin from the height of the feet/runners.
• First test batch resulted in a single bottle broken. The bottom of the bottle simply detached from the sides. The glass stayed in the crate.
• Use protective clothing and face shield when operating the bath.

Thanks to everyone who posted pictures and ideas to get me this far.

-Nat West, Portland Oregon

[Wes Cherry]

Great writeup Nat!

My pasteurizer is quite similar (Nat tipped me to the idea of using a
macro bin and an on demand hot water heater).

I elected to use an insulated bin that is normally used for ocean
fishing. The Promens DX318
http://stjohn.promens.com/ca/mproduct/view/16
It fits 5 standard rectangular milk crates, each with 18 bottles.

It already has a drain plug and the insulation in the body and the lid
helps with standing losses. Covered, overnight, the bath temperature
drops by less than 10 deg C from pasteurization temps.

I also used an on-demand electric heater vs a gas heater. This was
mainly because my electrical panel is right next to the pasteurization
area in my cider house. I also do not have natural gas service and I
didn't want to mess with propane tanks and the venting issues of the
exhaust gas.
The unit is rated at 28kW. I got the sanitation (80degC) version of
this:
http://eemaxinc.com/EX280T2T

While setting it up, I accidentally burned out one of the three heater
cores so I am only going on 2/3s the power. That is plenty to get
the bath temp up in a short time and keep it there, so this 19kW unit
would be sufficient:
http://eemaxinc.com/EX190TC

I used PVC fittings -- as Nat says CPVC would have been better. The
PVC gets a little soft but so far it has held up.

I use an electric chain hoist to lift the milk crates in and out of
the pasteurizer. My back is thankful for that. Also when lifting
by hand you end up placing your face right near the bottles which
could explode, especially during the jostling of transfer. I have
had 2 bottle failures so far - one just like Nat's with the bottom
detaching from the sides. On the other a cap popped off. Probably
from a bad crimp or overfill of the bottle.

[Alasdair Keddie]

Both designs look great, thanks for the write ups.

Unfortunately, neither the MacroBin or Promens units seem to be available in the UK, looks like I still need to find an old stainless steel sink.

[Wes Cherry]

Something similar should be available from the Eurozone.   Promens is an Icelandic based multinational company and the Italians were the first to pioneer plastic apple harvest bins.   

MacX bins are another option.

At a smaller scale, a galvanized livestock watering trough would work.    Something like this

http://midamericalivestockequipment.com/water-tanks.htm

The most important thing is to have a lid because at pasteurization temps most thermal loss is thru evaporation of water rather than conductive losses thru the tank walls.    It's rather remarkable -- at 15C ambient temp, the evaporation and radiation energy loss for a tank of water at 70C is 6x that of the loss thru bare steel tank walls.

http://www.engineeringtoolbox.com/heat-loss-open-water-tanks-d_286.html

Even 1" of insulation on the tank walls brings those losses down to negligible values.

-'//es Cherry

w...@dragonsheadcider.com

Vashon WA, USA

On Jun 14, 2012, at 12:11 PM, Alasdair Keddie wrote:

Both designs look great, thanks for the write ups.

Unfortunately, neither the MacroBin or Promens units seem to be available in the UK, looks like I still need to find an old stainless steel sink.

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[Wes Cherry]

There is a special sanitation version of the eemax unit which has a higher temp limit.

http://www.eemaxinc.com/EX280T2T-S

This is a 3 core unit   A 2 core unit would be sufficient (one of my cores burnt out and it still works well)

http://www.eemaxinc.com/EX190TC-S

I found best prices at pexsupply.com.

Circulation is constant using a radiant floor pump.  http://www.pexsupply.com/Grundfos-59896341-UPS15-58FC-3-Speed-Circulator-Pump-1-25-HP-115-volt-4701000-p

I watch the bath temp and if it gets above 73c or so then I turn the heaters off via the breaker panel.  Running the heaters at their design limit could be hard on the element power switching triacs since they are cooled by the incoming water.

These electric heaters really suck power.  120A for the 3 core unit.  If you are not near an electrical panel then you could spend a fortune on wire to feed the unit.   If venting or outside use is possible I would go with a gas fired unit.   Check radiant floor boilers for options.   

I believe nat west is using a gas powered tankless water heater with a replacement circuit board to surpass its 140f limit.

I have some ideas about a DIY tankless design that could be done on the cheap.   Essentially it involves using a large stainless pot or sanke keg with a larger hole cut in the top   Mount 3 or 4 5500 watt domestic hot water heating elements.   Weld a fitting to pump recirc water to the the keg at the bottom and another at the top which then spills out to the pasteurizer bath.   

There are a number of safety features built into the tankless heaters so this design isn't as safe (boiling over, shock, burning out elements etc...).   You could add thermostatic control, though switching 5000 watts under electrical control isn't super trivial.   

You could also make this gas fired by heating the keg using a wok burner or a turkey fryer burner.

-'//es

Sent using the 4S

On Sep 26, 2012, at 10:04 AM, Bent Fender <fende...@gmail.com> wrote:

Wes,
How did you get the tankless water heaters you mentioned to reach temps above the stated value of 140 F as the manufactures pages says they are programed to. Did you get a different controller? And do you do a constant recirculation through the tankless, or do you have a micro-controller that switches the pump on and off during your pasteurization time? If you bypassed the manufactures controller how did you program the unit to reach 160 F or slightly higher.
Thanks
~Jeremiah

[jim gerlach]

Wes,

What do you think about providing the heat via diesel low volume stream pressure washer? I think they are rated up to 240+ degrees F. As long as you could design the enclosure to evenly distribute the heat it seems much more efficient that heating a huge volume of water. 

And you get double duty out of a piece of cleaning equipment.  I've got my eye on one and am trying to justify the sticker shock.

jim gerlach

[Wes Cherry]

You'd want to ramp up the heat applied to the bottles.   The shock of 240F steam will cause the bottles to crack.

I experimented with sprinkling cold water on hot bottles to accelerate cooling after the pasteurizer bath  with spectacular results.   

I also played around with spraying 75c (~170F) water on bottles.   No exploding bottles, but time to pasteurize to 50 PUs was 80 minutes iiirc vs 20 to 30 for bath.

You might be able to build a conveyor belt tunnel pasteurizer using long stainless tubes with holes drilled into them to jet the steam to the passing bottles   Introduce the steam to the tubes on the bottle exit end.   Maybe it will cool enough to provide a thermal gradient from one end to another.   Introducing cold water partway down the tube may help with a steeper thermal gradient.

-'//es

On Sep 26, 2012, at 2:58 PM, jim gerlach <jimge...@mac.com> wrote:

Wes,

What do you think about providing the heat via diesel low volume stream pressure washer? I think they are rated up to 240+ degrees F. As long as you could design the enclosure to evenly tdistribute the heat it seems much more efficient that heating a huge volume of water. 

[Rich Anderson]

I use the diesel boiler on my pressure cleaner. The water is recalculated with a small electric pump, and the pump on the pressure cleaner is bypassed (it is noisy and the seals cannot take the heat).  I set the boiler thermostat at approximately 200 F and pasteurize 100 750’s in approximately 30-35  minutes. Works fine however the boiler on the pressure cleaner is not particularly efficient about requiring approximately  .75 gallon of fuel per hour.  

 

 

 

[Bent Fender]

Here is a plan fore what I am thinking of building, we have a bottling machine that outputs about 6 bpm at 22oz, we currently brew ginger soda we are applying for our liquor license through OLCC for cider production. The idea is to load the first barrel with bottles and add the water till the proper PU level has been reached then drain the tanks and push the water into the next tank, this will allow the bottles to cool incrementally till they hit handling temperature where they will be pulled and labeled. We have been using this method using only one tank with pretty good success occasionally we will lose a bottle due to what i believe is  a defect in the bottles and an occasional leaky crown cap.

Eemax told me that the water input must be bellow 110f (43c) as the units can not self  regulate their temperature and the control board could burn up. The problem here is needing to add in cold water to the system to bring the water temp down to 110f before entering the heater. I am concerned about the shaky science with the PU system, as we have had the real experience of exploding bottles at an account holders shop, with so many floating variables it seems like a difficult system to get to work out right. So we would like to keep the pasteurization temp constant for the duration of the pasteurization time. I have thought about using the hot water elements at the bottom of each barrel to keep the temps up and just recirculating the water through the pump system until time has expired then passing the water to the next tank, then all the thankless heater is doing is preheating the water to the baths for a speeder fill time.

Thoughts?


Jeremiah Fender

[Bent Fender]

Wes, also wanted to thank you for your reply. thanks for contributing so much, and the links were very helpful.

[Wes Cherry]

I also talked with an eemax engineer and he warned me about recirculating hot water.

After reviewing the data sheet and doing some thermal resistance heat flow calcs, I convinced myself that it was ok, though on the edge of the operating envelope.

To view the calcs graphically, check the data sheet.

http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00002263.pdf

If you look at Figure 2 the device is ok with 40 amps thru it when the case temp is held < 85 C.   85 C is the knee on the graph where the current handling ability without blowing drops though.  The triac has to dissipate approximately 46 watts at 40 amps and that's a lot given the incoming water is around 70 C.

The actual calculations of heat flow from the semiconductor junction to the water are a little more involved, but this gives you an idea.

The triacs are a cheap part ($5 from mouser.com vs $35 ish from eemax) so I'm not too worried if they blow.   So far I haven't had a problem.

I doubt the control board itself would burn up.   All the thermal issues are with the triac.

I'm still a little nervous about using the eemax unit over the long term.   I suggest looking into radiant heat boilers which are designed for a higher operating temperature.   The downside is they cost about 2x price of the eemax.

-'//es Cherry

w...@dragonsheadcider.com

Vashon WA, USA

[Will van Schaik]

This thread has been a life saver, hope you don't mind me bringing it back to life. 

I'm based in Australia and will be following much of the above process - 

1. Bath - Using a 780L "Nally Tank" with Lid
2. Piping - Shark Bite Plumbing, push to connect brass fittings and pipe
3. Pump - Grundfos comfort 15-14 b pm
4. Heating - This is where I need some advice. In Australia the range or options for commercial hot water devices is a little more limited. I want to go with electric sources but would like some advice on which option. 
   1. 315 Liter Tank Commercial Hot Water Heater - Can get a used one for around $1,400 delivered
   2. Over the side 2400 w Immersible Heating Elements x 4 or 5 - $80 each
   3. Screw or Plug In Heating Elements, drilling holes in the tub to fit 2 x 6000 or 9,000 W Heating Elements - Element Incoloy Low Watt Density Straight 6.0kW - $150 each
   4. Custom Made Immersion Elements - Talking with Hotco today

While I want to save some money, I also understand trying to save money might add time and labor to setup. My concern with the heating elements is it might melt the Nally tank. I would've loved to get some sort of Eemax like Wes mentioned but finding one in my price range / used on ebay is hard. I've even gone through FB Marketplace with NYC and LA as my search parameters. 

I have 2x3 Phase Power at 32 Amps, 1 x 15amp single phase and normal 10amp single phase at my warehouse. Will be pasteurizing 250ml sleek cans. 

Would love some advice or opinions on heating options. 

Thanks,

Will

[David]

I would use a stainless tank rather than plastic, even if you have to get one made. I would not use over the side elements and even the manufacturer says not to be used in such a way. Could all too easily end in disaster with melted tank and electrocuted operator. Off the shelf elements are going to be your cheapest option and you have plenty of electricity supply by the sound of it, I would use several around the tank rather than one big one and wouldn't use a pump.

If you do get a tank made, I would design it so you can insulate it, they lose a lot of heat which is money. My current (uninsulated) tank is about 200 litres and I am considering making a new slightly bigger one that is insulated. I use 3 x 3kw electric elements that are meant for washing machines really. Difficult to find these days as everyone has switched to 2.4kw elements in order to save the planet. Makes no sense as it still takes the same amount of electric whatever the element size, just takes longer.

Another bonus with custom made tanks is that you can design them to hold a number of whatever crates you are going to use. Crates allow multiple bottles/cans to be lifted in and out easily. I use milk crates that hold 20 x 75cl bottles but they are getting too heavy for me, for my next trick the tank will be designed to hold a certain number of crates that hold 12 bottles.

Cost is always a consideration but try and make the easiest system to operate, it works out for the best in the long run. You also need to size it so you can fill and empty it with a quick turnaround, ie if there isn't enough heat going in it will be terribly slow, if  there is too much heat you can't keep up with the turnaround..

Good luck

David

[Wes Cherry]

I gave up on eemax.   Janky, slow, fault prone.    Electric just takes waaaay to much current to do this well.

Now using a propane powered instant 200kbtu hot water heater that is rated to 80c on recirc.  Works great.

 

Plastic insulated tote holds 5 crates for 95 750 btls.    About 20 minutes a batch   Keep in mind most heat loss is evaporative so a cover is way more important than side insulation.  (~Like 10x more heat loss).   A well covered macro bin would work well.

Don’t forget a filter in the recirc loop.  A simple under sink style filter is fine.  Use largest micron filters u can get.  (5 micron or less)

-'//es Cherry

Dragon's Head Cider

Vashon Island, Wa US

www.dragonsheadcider.com

On Jan 10, 2025, at 11:47 AM, David <peasgoo...@gmail.com> wrote:

I would use a stainless tank rather than plastic, even if you have to get one made. I would not use over the side elements and even the manufacturer says not to be used in such a way. Could all too easily end in disaster with melted tank and electrocuted operator. Off the shelf elements are going to be your cheapest option and you have plenty of electricity supply by the sound of it, I would use several around the tank rather than one big one and wouldn't use a pump.

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