Temperature and activity

[ericmark]

During the summer months I turn the central heating down don’t want to warm up a house when latter in the day it is going to get too hot. But the result is the average room temperature is lower in the summer and 25 litres takes a lot of heating and cooling so winter average is around the 18ºC but summer more like 16ºC not that much difference but enough to mean time in fermentor is increased.

I am only really talking about maximum of 4ºC between room temperature and ideal brewing temperature and when a start a brew just putting a body warmer around the brew is enough. But as the fermenting slows then to maintain at 20ºC means some extra heat I normally use an old under floor demo heating tile 18W which works well.

However it would be nice not to have to bother with a heater so my thoughts were using different yeast. I tried using Youngs Lager Yeast which works exactly the same as the kit supplied yeast after 20 days s.g. still at 1.012 looking for around 1.006 so heating tile has gone under the fermentor again.

There must be 100’s of yeasts and I am sure there is one which will ferment a couple of degrees cooler. However it would mean once I got the yeast transferring it from brew to brew and I am uncertain on the likelihood of also transferring unwanted stuff.

I read about brew making history and how the family stirring stick was guarded as it would transfer yeast into the brew so I assume very little yeast is required. One site says half the yeast means a difference in just half and hour in brew time. It also points out not enough yeast will allow wild yeasts to get a hold instead.

So I am not sure if it is worth using different yeast and of course how much the yeast will alter the taste. So inviting thoughts on using different yeasts and advice on how they will likely affect the brew.

As summer advances the problem will go but as autumn comes it will raise it’s head again. Which raises another question should one change the yeast or even the beer to match the seasons.

 

[jonnymorris]

I like your thinking but am not convinced it's the way to go. You'd be better off controlling your temperature via, in an ideal (homebrew) world, building a brew fridge and then choosing your yeast to suit the flavour profile you're after.

 

[JamesMcS]

A cheap alternative that's worked well for me is a submersible fish tank heater - thread the power cable through a bung, I use cling film wrapped around the cable and pushed into the bung to get a good-ish seal, and robert's your father's brother - I picked up a few 50w ones off the bay for 6 quid each, they've served me well for the last few brews.

There was some chat about them being difficult to clean, but a bottle brush and some steriliser doors the trick for me

 

[jondi11]

A cheap alternative that's worked well for me is a submersible fish tank heater - thread the power cable through a bung, I use cling film wrapped around the cable and pushed into the bung to get a good-ish seal, and robert's your father's brother - I picked up a few 50w ones off the bay for 6 quid each, they've served me well for the last few brews.

There was some chat about them being difficult to clean, but a bottle brush and some steriliser doors the trick for me

I was thinking of doing this, I am going to be doing my first Beer home brew at the end of the week, its a pilsner.
Wondering to keep it in kitchen for first brew, south facing with patio doors in open plan kitchen stays quite warm this time of year around 20 - 21c, not sure of through the night though.

 

[JamesMcS]

Grab yourself a min max thermometer, from what I've read a constant temp is important for a decent brew. The heaters have a little thermostat dial on them so they'll be off during the day, then they'll keep your beer nice and warm overnight.

But if the room only fluctuates a couple of degrees over 24 hours, I reckon you'll be alright.

 

[JamesMcS]

I did have to tie a knot in the power cables though, the heaters kept slipping down into the mix and they're not supposed to go too deep

 

[jondi11]

I have now purchased a Aquarium heater to regulate temperature, we're supposed to have warm days and cold nights this week. Why do you have pipes off your air locks?

 

[ericmark]

50W must be over kill. I use a 18W underfloor heating tile when I want to lift the temperature and this in 24 hours will raise the temperature about 6 degrees above ambient using two periods on and one off over 24 hours raised the temperature from around 17 degrees to 22 degrees then left it to slowly cool again with the hope it would ensure the fermenting had finished. It's now been 25 days from start and by now all other brews would have been finished but s.g. still sitting at 1.013 used camera to get accuracy as 2 points per division. The air lock activity is around one bubble every 2 minutes but when I took the sample it was full of gas and it took ages to settle to take reading.

So it would seem this yeast slows down more than most at the end. It is interesting as it was completely unexpected and lucky I used hydrometer otherwise I would be bottling too early also lucky done the brew before or I would not know to expect a final s.g. of 1.006.

The idea of fish tank heaters is good could easy fit stuffing glands in the lid to seal but think would use at least two in series from experience with under floor heating tile at 18 watt I would say want around 10 watt to keep the brew that couple of degrees warmer without producing hot spots three in series would give 17 watt four would give 12.5 watt which would give a larger surface area too so less likely to bake on the yeast and give a genial boost without killing all the yeast that touches the heater. I see you can get 25W versions two of them in series may be better.

What I was thinking was using a dimmer switch to reduce my tile to around 10W but to me heat should come from below as other wise you will get what is shown in the school boy experiment where water is boiled in top of test tube but weighted ice is still present at the bottom.

For second heater I was looking at old aluminium caravan step and a old flee catcher with a 15W piggy bulb with old body warmer draped over the three I would really have to do nothing to build it just place them all together. However I hope the weather will improve and this will not be required until next winter.

But I have learnt lesson with lager yeast and will avoid it in the future. I know lager means to store but I wanted to store after it was bottled not before. The lager with same yeast now been fermenting 100 days and still going.

 

[JamesMcS]

I went by the product description, they had a number of different heaters for different size tanks - 50w was suitable for up to 25 litres, and I do 23 litre brews at the moment. I checked the thermo strips on the buckets every day for the first couple of weeks at different times and they all showed a steady 21 degrees.

Perhaps under floor heating is more efficient - but there's a trade off with cost there, I'm sure

 

[JamesMcS]

The pipes are blow off tubes - sometimes the brew foams out of the airlock, so to be on the safe side I run the tubing into a jug full of sterilising solution - anything that comes up through the airlock ends up in there, and there's no risk of contaminating the lovely beer :-)

 

[Blue_Moon]

What diameter tube do you use?

 

[JamesMcS]

I picked up some 5/16 house but it's a really tight fit, I had to heat the end of the pipe and pre stretch it using a ball point pen lid.

 

[ericmark]

Using a thermostat the general temperature will be steady but what about right next to the heater. It is all to do with mark/space times. Switch a heater on and off 30 times a minute like a lamp dimmer will do and no hot spots. Do it every 10 minutes and the brew near to heater will be overheating when on for 10 and off for 40 minutes but not on for 10 and off for 40 seconds it's all down to time. But if the heater is on for 40 minutes and off for 10 then likely even just before switch off the unit will not be too hot.

Fish will not swim to close to a heater which is too hot yeast does not have the option. A fish tank is not covered with insulation or you can't see fish but a fermentor is or at least it should be.

So closer element is to the point where it is on 24/7 the less anything close will be overheated. There is with any thermostat a on and off temperature my room one now electronic is 0.5 degrees before that the mechanical one was 2 degrees and the distance between thermostat and element will vary the overshoot as will element size.

With electronic switching twice a second is not a problem but with mechanical it would not last long I don't know if electronic or mechanical so it may be electronic in which case not a problem but if mechanical then either the contacts will burn out or the local temperature will be excessive.

From experience I would say 10W is enough for a 30 litre container with 25 litres of liquid to raise it 4 degrees above ambient when it is insulated with a coat. Clearly if looking at 10 degrees with no insulation then yes it will need more power but even plastic insulates better than glass of a fish tank so to me 50W is way too big.

 

[Arch41c]

Hmmm I use a 100w heater in my 180l fish tank and it's kept it happily at 25c and when I had my baby tank (21l) a 10w kept that at a steady 23c, so I'm guessing a 20w tropical heater would be sufficient for a 25l brew bucket?

 

[JamesMcS]

Looking at my purchase history, I can see that it is indeed 25w heaters I went for. Dummy