How to Set up a Water Bath for your FV

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Fermenting Ale yeasts prefer a steady temperature to do their job properly, usually in the range 18-21*C. This method describes setting up a simple, cheap and effective water bath in which to place your FV, which can be used in the colder months of the year to give a consistent temperature for your brew. However if your FV has a bottom tap it is not recommended.

WHAT'S NEEDED

- A Laundry or Builders Trug (typically from Wilko like this for about £4)
trug1.jpg

BUT before you buy, measure your FV and make sure it will fit inside the trug with about 50mm gap around as a minimum. Note that if you have the Youngs FV it fits inside the Wilko trug.

- An Aquarium Heater like this (typically off ebay for about £7 upwards) you need the type with a built in thermostat.
heater.jpg

A 50 watt heater should cover most needs. However if you are intending to use the bath in an unheated building which gets extremely cold you might consider a bigger wattage heater. Note bigger heaters are longer and will require more water in your bath to cover them. Suggest you check dimensions before you proceed

- A Thermometer

- Optional;
a roll of bubble wrap and some old towels or a blanket

SETTING UP

You will need to set up your water bath before you use it for a brew to achieve the desired temperature in the bath. This will be done with water, when the room temperature is below about 17*C, so that the heater will work. Be aware that the heaters are not on 24/7 they are thermostatically controlled. Note the thermostatic controller on the heaters are not very accurate so don't rely on the indicated temperature setting.


Suggested temperature for set up and for brewing is 19*C.

Optional - To insulate the outside of the trub, tape bubble wrap around the outside

1. Using the suction pads, fix the aquarium heater to the inside of the trug. Fit the heater in the vertical position, and try to get it positioned to give a 20mm gap or so between the bottom of the heater and the bottom of the trug. Initially set up the heater control to about 19*C
2. Put about 10 litres of water at about 19*C into the trug.
3. Fill your FV with 23 litres of water at about 19*C, and carefully lower into the trug.
4. Switch on the heater. Note that some designs of heater have small light down the side which is on when the heater is heating.
5. Check the temperature in the bath again using your thermometer.
6. Cover the whole with an old blanket or similar.
7. Leave it for an hour or two and check the temperature. Adjust the thermostat in very small changes at a time to get about 19*C in the bath. This may take a few hours, less if you are lucky with your settings. Note there will be a small temperature variation around the bath.
8. When the bath is finally 19*C you have finished. The heater can be switched off.
9. Before dismantling, with insulating tape or similar, it is useful to mark where the suction pad positions are, and the water levels in the bath, both with and without the FV inside. This will help set up next time.

USING WITH A BREW

1. Set up water bath with trug and heater as before, and fill with about 10 litres of water at about 19*C.
2. Lower FV inside and switch on heater.
3. Cover whole with blankets or towels to insulate, and then leave it.
4. That's it, job done.

TIPS
- Occasional checking of the water bath temperature may be needed when in use. Rarely fine tuning up or down is needed with different room temperatures.
- Put a splash of bleach in the water bath.This inhibits biological growth which can sometimes form.
- If you need to remove the FV from the water bath for any reason, turn the heater OFF before removing the FV. And don't don't forget to turn it ON again after the FV is returned to the water bath.
- Depending on the conditions you may lose a small amount of water from the bath due to evaparation. A small top up may be needed, so keep an eye on the water bath water level.
- The heater is obviously water tight. However be sure to place the heater electrical plug where it cannot accidently fall into the water bath. Water and electricity don't mix!

Finally
Here's one I made earlier (!), and in use with the covering towel pulled back a little. Not much to look at but effective


1643735898749.png



water bath.jpg
 
Last edited by a moderator:
well done Terry, thats really useful. I like the simple yet effective solution, which is cheap as well. I'm definately going to do this.
 
Good guide Terry. I started out using this method and while I now have a fermentation fridge I still use the water bath when I have more than one brew on the go.
The water does get a bit murky after a while and someone on here suggested using a little Starsan in the water to counteract this. I tried the Starsan and it did help but I found it corroded the metal handle on the fermentor. I'm not sure whether bleach would have the same effect, have you tried it?
 
Good guide Terry. I started out using this method and while I now have a fermentation fridge I still use the water bath when I have more than one brew on the go.
The water does get a bit murky after a while and someone on here suggested using a little Starsan in the water to counteract this. I tried the Starsan and it did help but I found it corroded the metal handle on the fermentor. I'm not sure whether bleach would have the same effect, have you tried it?
I have suggested using bleach in 'Tips' in the write up because that's what I use. In the set up I have described, (based on what I do) the water level does not come up further than about 2/3 up the FV, and so the water gets nowhere near the FV handles. I deliberately kept the water level low because I did not want the FV and its contents to have any possibility of floating!
 
I'm going to do this for my first foray into WOWs and have ordered a heater and a cheapy digital thermometer from eBay this very lunchtime.

For beer I have two fermentation fridges in my garage. For the WOWs I'll be keeping those in my utility which whilst heated can get a bit cold during the day. Planning to use one of those plastic storage containers you get in Wilkos and the likes for the bath, picking one big enough to fit 2 x 1 gallon demijohns.

Thanks for the guide.
 
I have suggested using bleach in 'Tips' in the write up because that's what I use. In the set up I have described, (based on what I do) the water level does not come up further than about 2/3 up the FV, and so the water gets nowhere near the FV handles. I deliberately kept the water level low because I did not want the FV and its contents to have any possibility of floating!

It was a Youngs 15 litre FV I was using at the time so the handle hangs a lot closer to the base. Yes, I've found too that if you have too much water in the trug the FV floats lol.
I found for my larger, wider FV that you can get much larger builders style trugs in Wickes, more expensive than the Wilko ones though, I think I paid about �£9.99 for mine.
 
If using inside the house rather than a cold garage, I'm finding a 25w heater copes fine.
 
I deliberately kept the water level low because I did not want the FV and its contents to have any possibility of floating!

I have found that letting my fv float as I siphon to my bottling bucket is a great trub/yeast filter - in fact I ve ditched my racking kane with trub filter for the last two bottling days.

I put my trug and fv out to the shed to cold crash for 24hrs before bottling.
Keeping a hand (and eye) on the fv as I siphon to my bottling bucket the far end slowly floats up and the the beer flows to the near side quicker then the yeast cake, helping maximise the amount of beer iget into my bottling bucket :-)

20160916_124935.jpg
 
Great post terry, I still recommend your starter guide to any one just beginning to brew. TBH I have a read through it once in while it doesn't hurt to go over the basics. Get them right and you're not pouring 40 pints down the drain.
 
I have found that letting my fv float as I siphon to my bottling bucket is a great trub/yeast filter - in fact I ve ditched my racking kane with trub filter for the last two bottling days.

I put my trug and fv out to the shed to cold crash for 24hrs before bottling.
Keeping a hand (and eye) on the fv as I siphon to my bottling bucket the far end slowly floats up and the the beer flows to the near side quicker then the yeast cake, helping maximise the amount of beer iget into my bottling bucket :-)

Do you know where your syphon tap came from.I can only find the little ones.
 
Great posting, I did this for the first time last winter and it made an incredible difference to my brews - a real consistent ferment right down to 1010 in most cases. I now almost prefer brewing in winter rather than summer fluctuating room temps, in fact I now stop brewing June-Aug.
 
Good guide Terry. I started out using this method and while I now have a fermentation fridge I still use the water bath when I have more than one brew on the go.
The water does get a bit murky after a while and someone on here suggested using a little Starsan in the water to counteract this. I tried the Starsan and it did help but I found it corroded the metal handle on the fermentor. I'm not sure whether bleach would have the same effect, have you tried it?

starsan wont affect any wild yeast in the water tho....
 
Fermenting Ale yeasts prefer a steady temperature to do their job properly, usually in the range 18-21*C. This method describes setting up a simple, cheap and effective water bath in which to place your FV, which can be used in the colder months of the year to give a consistent temperature for your brew. However if your FV has a bottom tap it is not recommended.


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this looks awesome, i never thought about doing something like this tbh so thank you very much - i imagine its alot more economical to run then a fridge dedicated to a keg !
 
I've just put mine into service again now the house temps have dropped after the summer - brewed an AG beer last Sunday, airlock stopped bubbling a day ago so dropped the hydrometer in today (Sat) and it's down to 1010 already. I'm sure that consistency is down to temp control.
 
Great Guide Terry. I know I'll be directing members here in the coming months when we get the normal 'My brew is too cold' :thumb:
I echo the comments about Terry's water bath set up. A great idea that I have used for my first batch from a microbrewery kit. That said, my own problem was not keeping the wort warm, but keeping it cool enough for fermentation. In a spare bedroom with radiators turned almost off, the ambient temperature remained doggedly at 22C inspite of it being mid November. In the end I moved the whole set up - water bath and FV - into the garage and sat inside an old sleeping bag. Temperatures are now in 18-20C range I need.
 
That was really helpful, not least because it dealt with the problems I've had in coming back to brewing after over 30 years and trying to set it up to work in the greenhouse. I'd taken the more brutal approach of cutting a hole in the lid of the FV and dangling the heater down the middle. My reasoning was that this would give effective heating throughout the brewing liquid. How does it work with the water bath? Is the temperature even, or is it warm near the heater and much cooler opposite it?
 

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