Off grid fermentation temperature control?

Discuss all aspects of fermentation
User avatar
Jeltz
Piss Artist
Posts: 177
Joined: Fri Sep 21, 2012 9:42 am
Location: Swindon

Off grid fermentation temperature control?

Post by Jeltz » Sun Mar 01, 2020 12:27 pm

I separated from my wife last year and have moved in with a new partner but alas the house is small and there isn't the space indoors to ferment.

Weather permitting I can brew outside but fermentation would have to take place in a metal shed away from the house without a power supply and running power to it isn't viable.

Long term we'll put a brew shed/summer house close to the house and run electrics to it but that isn't going to happen until my ex manages to buy me out, or we sell the house, but that's not likely to be for 6 months +

In the meantime I could, to an extent, work with the seasons using lager yeast in the winter and Kveik yeast in the summer but I still think there would be need for heating; I'm looking at solutions such as solar panels, a battery for a caravan or boat, a generators but it would have to be quite as it's a residential area. I have absolutely no experience with this kind of stuff, I'm presuming that its all 12V, so that would be an 12v STC-1000, I'm thinking that 35W - 45W heated car seat covers might be viable as fermenter heaters, but I have no idea how to calculate how long they could heat for.

Obviously there would need to be significant insulation and cold crashing would be weather dependent, but have people managed to sort out similar solutions or have other ideas?
Rega

guypettigrew
Even further under the Table
Posts: 2626
Joined: Mon Mar 22, 2010 7:10 pm
Location: Christchurch, Dorset

Re: Off grid fermentation temperature control?

Post by guypettigrew » Sun Mar 01, 2020 3:52 pm

Are you looking to heat the beer as it ferments? If you are, then one of these might do it for you. people used to use them for fermenting purposes years ago. Proper cleaning and sanitisation would be essential.

Guy

brewpete
Piss Artist
Posts: 157
Joined: Sun Dec 09, 2012 11:13 am

Re: Off grid fermentation temperature control?

Post by brewpete » Sun Mar 01, 2020 5:01 pm

You can get 12v electric blankets

guypettigrew
Even further under the Table
Posts: 2626
Joined: Mon Mar 22, 2010 7:10 pm
Location: Christchurch, Dorset

Re: Off grid fermentation temperature control?

Post by guypettigrew » Sun Mar 01, 2020 7:23 pm

Triple post. Getting a bit muddled here, and I haven't started on the home brew yet this evening!

Guy
Last edited by guypettigrew on Sun Mar 01, 2020 7:25 pm, edited 1 time in total.

guypettigrew
Even further under the Table
Posts: 2626
Joined: Mon Mar 22, 2010 7:10 pm
Location: Christchurch, Dorset

Re: Off grid fermentation temperature control?

Post by guypettigrew » Sun Mar 01, 2020 7:24 pm

Double post.

Rookie
Falling off the Barstool
Posts: 3552
Joined: Fri Nov 23, 2007 5:30 pm
Location: Fort Wayne, Indiana

Re: Off grid fermentation temperature control?

Post by Rookie » Sun Mar 01, 2020 7:58 pm

How far from the house?
I'm just here for the beer.

User avatar
Kev888
So far gone I'm on the way back again!
Posts: 7701
Joined: Fri Mar 19, 2010 6:22 pm
Location: Derbyshire, UK

Re: Off grid fermentation temperature control?

Post by Kev888 » Sun Mar 01, 2020 8:03 pm

Not sure how well you could insulate a FV, but you'd really need to keep the power requirements right down if running by off-grid electricity without a generator. By way of example if you managed to insulate well enough (and it would be an 'if' in mid winter) that an average of 25watts was sufficient to heat then this would equate to 600watt-hours (0.6kwh) per day. On a 12volt system that would equate to 50Ah (amp-hours) used per day.

Running something like leisure-type batteries could supply that if you could swap them daily throughout fermentation, charging one in the house whilst the other runs the heater. Though the batteries would need to be bigger than needed, say around 80Ah or more, as even leisure types of lead acid battery don't like being deeply discharged (standard car batteries might need to be much more). It might also damage them if you forget and let them discharge too far (not sure if one can get pre-built protection circuits for that). I haven't yet seen more modern styles of battery pack in sufficiently large capacities, not off the shelf anyway, though they may exist.

Solar PV cells are hard to pin down, as the ratings you see are rather optimistic even for average UK summer conditions and almost a mockery for our winters (of short, dull days with low sun). I'd guess that to keep a battery topped up automatically, you'd be looking at several hundred alleged watt's worth of panel. Which could be done, but is getting hair-raisingly costly and even then my guestimate could be way short for some conditions.

Other possibilities include things like gas heaters, which would be reliable but they're difficult to control and arguably less safe, not sure I'd want to heat a small chamber with one for instance. Overall.. I can't help but think that If even a low-voltage cable (rather than mains) could be run out there, supplying say 12volts and a couple of amps, it would likely be both the easiest and cheapest option.
Kev

brewpete
Piss Artist
Posts: 157
Joined: Sun Dec 09, 2012 11:13 am

Re: Off grid fermentation temperature control?

Post by brewpete » Sun Mar 01, 2020 8:28 pm

What about one of those camping caravan mains supply cables with a safety switch built in seen people use them continue for months on campsites

guypettigrew
Even further under the Table
Posts: 2626
Joined: Mon Mar 22, 2010 7:10 pm
Location: Christchurch, Dorset

Re: Off grid fermentation temperature control?

Post by guypettigrew » Sun Mar 01, 2020 8:57 pm

Oops. Just read the OP again. Having a really good evening here--not!

You don't have room in the house to ferment? A plastic 25L bucket takes up very little space. Surely you can fit one in for the time it takes to ferment?

Guy

User avatar
rpruen
Steady Drinker
Posts: 48
Joined: Sun Jan 05, 2020 3:29 pm
Location: Burnham On Sea, Somerset
Contact:

Re: Off grid fermentation temperature control?

Post by rpruen » Sun Mar 01, 2020 9:30 pm

I would go for really good insulation and a heater pad for a car seat teamed up with a 160W solar panel. You can add a 100Ah leisure battery and charge controller to that, so as to have temperature control at night. In the depths of winter you might need to swap batteries to keep up.

Here are links to some of the kit you will need


Over discharge protection circuit
https://www.amazon.co.uk/Digital-Batter ... B07929Y5SZ
Charge controller and Panels
https://www.amazon.co.uk/Solarset-160-W ... 50&sr=1-12
Battery
https://www.amazon.co.uk/100Ah-Cycle-Ba ... B00TOKAEXU
Heater pad
https://www.amazon.co.uk/QuickShop-200m ... ZSZ791XRCS
Temp controller
https://www.amazon.co.uk/KKmoon-Tempera ... ome-garden

Hope that helps

Richard

User avatar
Kev888
So far gone I'm on the way back again!
Posts: 7701
Joined: Fri Mar 19, 2010 6:22 pm
Location: Derbyshire, UK

Re: Off grid fermentation temperature control?

Post by Kev888 » Sun Mar 01, 2020 10:14 pm

Have you direct experience of that being sufficient, Richard? Several years ago a PV panel of that small size would have been of little use for a winter application like this, but I've no experience of more recent ones; it is genuinely great if they're improving that fast.
Kev

User avatar
rpruen
Steady Drinker
Posts: 48
Joined: Sun Jan 05, 2020 3:29 pm
Location: Burnham On Sea, Somerset
Contact:

Re: Off grid fermentation temperature control?

Post by rpruen » Sun Mar 01, 2020 11:25 pm

Kev888 wrote:
Sun Mar 01, 2020 10:14 pm
Have you direct experience of that being sufficient, Richard? Several years ago a PV panel of that small size would have been of little use for a winter application like this, but I've no experience of more recent ones; it is genuinely great if they're improving that fast.
I use a 60W solar panel to supply lighting for my pub in a shed. I have a whole load of LED lamps connected. Sure its hardly a heating load, but it is in the 150W range, and in the summer it keeps up just fine for daily use. in the winter you need to swap batteries for daily use, I hope to get a bigger panel soon. Modern panels are smaller and more efficient by leaps and bounds.

I'd assumed the fermenting vessel will be very well insulated (I wrap mine in hot water cylinder lagging) and my 200w heater goes on about 4 times per day for 3-5mins. The 160W panel should be able to keep up with that, even in the winter if it is kept clean and is properly placed.

I think the main thing is getting the beer well enough insulated.

Regards

User avatar
Kev888
So far gone I'm on the way back again!
Posts: 7701
Joined: Fri Mar 19, 2010 6:22 pm
Location: Derbyshire, UK

Re: Off grid fermentation temperature control?

Post by Kev888 » Mon Mar 02, 2020 9:13 am

Yes insulation is certainly the key for that kind of thing; it sounds like (at just a few five minute stints per day) you're using only about 50watt-hours (or less than 5ah at 12volts) which is remarkably little. If sufficiently well insulated for that to be so, perhaps a much lower power heater might be a better match, coming on more frequently but also more gently.

Whilst swapping batteries was still needed, then the PV panel seems a bit of a moot point. But presumably it would avoid the need to swap them as often or at all for more of the year, once longer brighter days begin.

Which perhaps also raises the question about cooling in summer, which is the other side of all this..
Kev

User avatar
vacant
Even further under the Table
Posts: 2167
Joined: Mon Aug 20, 2007 5:39 pm

Re: Off grid fermentation temperature control?

Post by vacant » Mon Mar 02, 2020 11:45 am

guypettigrew wrote:
Sun Mar 01, 2020 8:57 pm
You don't have room in the house to ferment? A plastic 25L bucket takes up very little space. Surely you can fit one in for the time it takes to ferment?
I was thinking that. I've fermented in a variety of storage containers from Wilko's as they have food-safe markings. They sell 28 & 32 ltr underbed storage boxes £5 each but I don't know if they are marked as food-safe.
I brew therefore I ... I .... forget

User avatar
rpruen
Steady Drinker
Posts: 48
Joined: Sun Jan 05, 2020 3:29 pm
Location: Burnham On Sea, Somerset
Contact:

Re: Off grid fermentation temperature control?

Post by rpruen » Mon Mar 02, 2020 4:00 pm

Kev888 wrote:
Mon Mar 02, 2020 9:13 am
Yes insulation is certainly the key for that kind of thing; it sounds like (at just a few five minute stints per day) you're using only about 50watt-hours (or less than 5ah at 12volts) which is remarkably little. If sufficiently well insulated for that to be so, perhaps a much lower power heater might be a better match, coming on more frequently but also more gently.

Whilst swapping batteries was still needed, then the PV panel seems a bit of a moot point. But presumably it would avoid the need to swap them as often or at all for more of the year, once longer brighter days begin.

Which perhaps also raises the question about cooling in summer, which is the other side of all this..
You can do cooling with TECs (the same devices as in 12v coolboxes) this will use more power, but in the summer you will have more power to play with. In full sun the panel will output more than 10A. You could DIY a cooling system easily enough, though you would need some metalworking skills. I can see using some water (glycol?) pipe coiled round the fermenter and a heat exchanger box with a small pump to circulate water that has been in contact with the cold side of the TEC and a large heatsink and fan for the hot side.

The idea of having the solar panel is that it cuts down on battery swaps, you would need to do that every few days to prolong the life of the battery. During the darkest part of the year you might have to swap batteries, depending on the weather, but I specified the panel to be big enough that it is likely you won't need to.

Yes a smaller heating pad would be a good idea, the heating requirements are not large, I calculated it on my own heating setup, and the element I could get was 200w. I agree it would be better if the heating was less granular, currently it has an almost 2deg C step from when the heater goes on to where it goes off. Sometimes I need to remove some lagging as the fermentation drives the temperature up (my current beer for example).

Regards

Richard

Post Reply