Controlling Fermenter Temperatures

[steve123]

Evening

I’m looking to create a chiller for my fermenter. And would value peoples thoughts. I currently have a brew fridge that works well for the standard plastic fermenters. I have a 100 l stainless steel pot that I’m using as a fermenter. I’m looking to do as cheap as possible, and don’t want to spend the cost of a maxi chiller.

my thoughts put a pond pump in a 70l cool box, connect it to the blue lay flat hose, wrap round fermenter, chill water in brew fridge and add ice when required,for heat wrap soil heater round, connect these to an inkbird, then insulate fermenter. Generally brew ipa, and cold crash at the end.

would this work effectively

I’ve had a search and found various solution but wanted to keep cost down and keep simple. I have everything needed apart from soil heater. Fermenter would be kept in garage

 

[nickjdavis]

why don't you use the chilling functionality of your brew fridge....what's stopping you using it with your stainless pot?

 

[steve123]

Pot is too big

 

[Justin Dean]

You could extend you fermenter fridge to make it bigger with some ply lined with insulation boards of polystyrene (wickes sell),

 

[steve123]

I like the idea of a cooling jacket, plus it gives me an option to ferment 2 at a time.

if it works as desired in the future I may consider investing in a maxi cooler

I have connected the lay flat hose to the pond pump and put in a bucket of water to see how it runs. The main issue is the hose kinks really easily affecting the flow, the pump is powerful to pump the water round but not sure the hose is the best opt

 

[Gerryjo]

I like the idea of a cooling jacket, plus it gives me an option to ferment 2 at a time.

if it works as desired in the future I may consider investing in a maxi cooler

I have connected the lay flat hose to the pond pump and put in a bucket of water to see how it runs. The main issue is the hose kinks really easily affecting the flow, the pump is powerful to pump the water round but not sure the hose is the best opt

I would second what @Justin Dean has mentioned about extending your fridge as this will give you more expansion and the option of using two heaters to maintain an ambient temperature and expanding your fermentation area.
Also if brewing lagers two at a time.

 

[steve123]

You could extend you fermenter fridge to make it bigger with some ply lined with insulation boards of polystyrene (wickes sell),

is there any designs for this? I will look into doing this for my plastic fermenters, to give option of doing 2 at a time which will be useful. I would still struggle to get the 100 litre in there as it sits on a stand as it has a slight conical bottom with an outlet on the base

thanks for suggestions

 

[RichardM]

is there any designs for this? I will look into doing this for my plastic fermenters, to give option of doing 2 at a time which will be useful. I would still struggle to get the 100 litre in there as it sits on a stand as it has a slight conical bottom with an outlet on the base

thanks for suggestions

I've seen something a long time ago, but can't remember where, where someone took the door off the fridge and used something like Kingspan to build an insulated box that butted up to the open fridge.

EDIT
This isn't what I was thinking of, but I like the idea Conical Fermenter fridge - Home Brew Forum (jimsbeerkit.co.uk)

 

[Bill_g]

I'd have to caveat this by saying it's only a gut feeling, but I would think that using plastic pipe throughout would be inefficient and your fridge would have to be kept very cold to make it work. Ideally the heat exchangers should be highly conductive e.g. copper pipe as it's readily available and works easily. Microbore pipe would be ideal as you could form it easily around your fermenter and have a coil in the fridge. The fridge wil most likely have a cold wall, probably the back. A flat spiral or serpentine in close contact with that face should improve efficiency. The two heat exchangers could be joined by plastic pipes and if they are long then insulating them would not be a bad idea. Also using antifreeze might be advisable to stop freezing up of the fridge heat exchanger.
if you cut holes in your fridge to bring the pipes in/out then be very careful where you drill. This seems pretty obvious but about a year ago you would have found the air in my workshop blue - I had not checked and I found (after cutting the hole) that my fermentation fridge used the metal side panels as the radiator. So in one careless moment I had converted a perfectly good fridge into an insulated box. Cutting a slot in the door is probably the absolute safest way.
My other thought is that copper pipe etc isn't cheap & the solution is probably less than ideal. So is it worth gritting your teeth and shelling out on a Maxichiller? I appreciate this argument may not wear well with your better half or other factors.

 

[steve123]

I'd have to caveat this by saying it's only a gut feeling, but I would think that using plastic pipe throughout would be inefficient and your fridge would have to be kept very cold to make it work. Ideally the heat exchangers should be highly conductive e.g. copper pipe as it's readily available and works easily. Microbore pipe would be ideal as you could form it easily around your fermenter and have a coil in the fridge. The fridge wil most likely have a cold wall, probably the back. A flat spiral or serpentine in close contact with that face should improve efficiency. The two heat exchangers could be joined by plastic pipes and if they are long then insulating them would not be a bad idea. Also using antifreeze might be advisable to stop freezing up of the fridge heat exchanger.
if you cut holes in your fridge to bring the pipes in/out then be very careful where you drill. This seems pretty obvious but about a year ago you would have found the air in my workshop blue - I had not checked and I found (after cutting the hole) that my fermentation fridge used the metal side panels as the radiator. So in one careless moment I had converted a perfectly good fridge into an insulated box. Cutting a slot in the door is probably the absolute safest way.
My other thought is that copper pipe etc isn't cheap & the solution is probably less than ideal. So is it worth gritting your teeth and shelling out on a Maxichiller? I appreciate this argument may not wear well with your better half or other factors.

thanks for the advice, I’m thinking long term about getting maxi chiller, just wanted to see if I could set something up that would work before investing in a maxi chiller. From what I’ve read most people add stainless steel directly inside the fermenter, I wanted to try and keep away from this to prevent risk of infection and reduce the extra cleaning.
I’m happy to put a hole in the fridge door to run in, how much copper tubing / micro bore pipe would I need to make it effective the vessel is 100l with a circumstance of i think 160 cm. even with a maxi chiller I could use the same pipe set up?
Not sure I understand what you meaning about bringing the pipes in and connecting them up, I don’t have much knowledge about the workings of fridges

 

[foxy]

Check this out, this is the Thermenter King, 12 volt. At the end of the video about the grain room Danny does introduce it. No fridge needed, can crash cool as well. Store away when not in use.

 

[Bill_g]

thanks for the advice, I’m thinking long term about getting maxi chiller, just wanted to see if I could set something up that would work before investing in a maxi chiller. From what I’ve read most people add stainless steel directly inside the fermenter, I wanted to try and keep away from this to prevent risk of infection and reduce the extra cleaning.
I’m happy to put a hole in the fridge door to run in, how much copper tubing / micro bore pipe would I need to make it effective the vessel is 100l with a circumstance of i think 160 cm. even with a maxi chiller I could use the same pipe set up?
Not sure I understand what you meaning about bringing the pipes in and connecting them up, I don’t have much knowledge about the workings of fridges

ok I can understand wanting to try building something up, I too get a lot of enjoyment from building things & experimenting.
Regarding the chiller please accept these are only ideas I've not tried doing this, but hopefully here is a better explanation of what I'm thinking & what I'd try if I was doing this myself.
I've attached a quick sketch, a picture being worth a thousand words & all that. Copper microbore tube is sold in 10m lengths which you could obviously join to make longer if you wished. But say you were to use one 10m length for each heat exchanger. (I can't see any good way to estimate or calculate whether this is enough or too much, I think it would have to be done by experiment). If the circumference of your fermenter is 160cm you would get about 6 turns. I think that this should be placed towards the top of the fermenter liquid level to take advantage of convection currents in the liquid (cooler liquid is more dense so falls). The pipe would need to be in good thermal contact with the fermenter, that is a bit of a challenge. That's why immersing the heat exchanger in the liquid would be better but I'd agree a nightmare to clean & sanitise.
Most fridges (but not all) have a radiator on the back which expels unwanted heat into the ambient. Most will have one cold face usually the inside back. This can easily be checked out by turning the fridge on & seeing what parts get cold fastest. If it has an ice box then it might well be the floor of the ice box. In my drawing I've assumed a larder fridge type with no ice box. But anyhow, the cold face is where you would need to site your second heat exchanger. Again it needs to be in good thermal contact. The two heat exchangers would be linked via flexible pipes & using the pump as shown in the diagram. I've assumed that the pipes would pass through a small hole or slot in the door.
I haven't shown any reservoir for the recirculating chiller fluid (water + anti-freeze) but one might be necessary to avoid air blocks. I would assume that you would use your temperature controller to turn on the fridge and the recirculation pump when chilling was required.
I suspect that the hardest part of all this will be to get good thermal contact of heat exchanger 1 to the fermenter and HE2 to the fridge cold face. The consequence of poor thermal contact would be that the fridge will need to work harder i.e. be on for longer, the result probably being a tendency to freeze up.
I hope that makes it clearer, but please take it all with a pinch of salt. I think that it will take a lot of experimentation to get it to work properly and by the time it's finished you will be the expert in the field! Good luck with the project & have fun.

 

[Bill_g]

This is a PS to my previous post.
It occurs to me that it would be feasible to replace the copper pipe heat exchanger in the fridge with a reservoir of water chilled by the fridge. The problem with this method would be that the fridge would have to run continuously to ensure that a reservoir of cold water was always available. Over the typical length of a fermentation this seems to me to be likely to consume more electricity. However as it may be quite difficult to get a copper pipe heat exchanger to work well inside the fridge, the reservoir might actually work better since it could be pre-chilled before fermentation starts to act as a 'store' of cold. The reservoir would have to be made out of something that conducts heat well e.g. metal and if it could be fitted with heat sink fins then it would work much better.

 

[steve123]

This is a PS to my previous post.
It occurs to me that it would be feasible to replace the copper pipe heat exchanger in the fridge with a reservoir of water chilled by the fridge. The problem with this method would be that the fridge would have to run continuously to ensure that a reservoir of cold water was always available. Over the typical length of a fermentation this seems to me to be likely to consume more electricity. However as it may be quite difficult to get a copper pipe heat exchanger to work well inside the fridge, the reservoir might actually work better since it could be pre-chilled before fermentation starts to act as a 'store' of cold. The reservoir would have to be made out of something that conducts heat well e.g. metal and if it could be fitted with heat sink fins then it would work much better.

many thanks for taking the time to write up this detailed explanation, I will give this some thought, this is what I was looking for, I appreciate your help.

 

[BlackRegent]

Check this out, this is the Thermenter King, 12 volt. At the end of the video about the grain room Danny does introduce it. No fridge needed, can crash cool as well. Store away when not in use.

I like the look of this, but I'm not holding my breath on it arriving in the UK

 

[steve123]

I like the look of this, but I'm not holding my breath on it arriving in the UK

Yeh looks great, hopefully get realised over hear and not too expensive !

 

[foxy]

I like the look of this, but I'm not holding my breath on it arriving in the UK

I think you will get them in the UK, just with covid and container shortage we haven't even got them here yet. I think the price was going to be around $250 AU so roughly half in UK + a bit extra.