To use a 4x4 term ... get in, sit down and hold tight
After many years and many trials of many different ideas, electric blankets are my preferred solution.
I use TWO double electric blankets on my 500 L fermenters and I find the three stage controller on them absolutely brilliant for controlling the temperature.
The insulation is MORE important, because yeast will accept a lower temperatures or higher temperatures what it properly hates is fluctuation.
I made some big long bungee cords [like big elastic bands] you can buy in bungee/ shock cord on eBay.
Put the electric blanket on first. Then tuck two layers of 10 mm foamy stuff over the top. You know the foamy stuff I mean... The sort of stuff you get in packing if you buy some technology. Looks a bit like white plastic polystyrene. It is brilliant stuff. If you have a box manufacturer near you, they sell it by the sheet, and will even cut it to size for you for absolutely no money.
Details on the ferment. Typically 400 L. I use a large pan stove to get the temperature up to start with to 20° C before pitching yeast. I use the hottest setting on the blanket to get it going and then slowly turned it down as the temperature increases. Note that as the yeast starts on this volume, the temperature will accelerate away on its own.
Try and be ahead of the curve. If you are aiming to get to 30° C. Turn the blankets off at 28.
If you need to cool. Remove the lid/sheet and give it a good stir* Depending on the shape of the fermenter, there could be a 4° temperature differential. Never ever remove the installation until you are done - typically it will only induce a violent temperature drop.
*Lets not get into over oxygenation. It just isn't relevant at these volumes I have proved it time and time again..
You DO NOT NEED a probe and an STC temperature controller. The temperature will not fluctuate fast enough for this to be any use whatsoever. Been there - got the hat, t shirt, pie etc. If really really feel the need, I have built a terrific one and it is for sale. Completely unnecessary.
However, a couple of things you do need.
1. A spoon or paddle long enough to reach the bottom of your fermenter. You will at some stage want to or need to stir it.
2. A handheld infrared laser guided thermometer. These are brilliant, quick and will save a lot of mess.
3. This is the hardest one to find .......enough time to check the temperature (takes 2 mins) every 12 hours, and adjust accordingly. Temperature changes will not be sudden, it is not like putting a pan on the stove. Do not compare this to smaller fermenters.
I have never ever lost a ferment or not had one start using this method. Indeed, what you will find is the bigger the vessel the easier they are to control not harder. They also make a different product. The shape of the fermenter can also affect it.
5 L, 25 L and 300 L with exactly the same recipe will result in a different finished flavour. Been there too and collected another T-shirt, pie, at and other suitable novelty items.
I don't know where you are planning to do this, but also please consider the amount of carbon dioxide. This stuff can kill you. I can't remember exactly but I think it is four times your fermenting volume of the CO2 is released. If this is in a confined space, think how you will ventilate it. If not where it will naturally flow (it is heavier than air)
These thoughts & observations are brought to you after 10 years of practical experience and more than a few technical courses.
and of course if you have any more questions, just shout up....
Statistics: Posted by Mash — Thu Dec 24, 2015 11:12 am
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