Fermentation temp controller advice

Hi everyone, new to brewing.

First batch is down and has been fluctuating +/- 4 degrees c (7.5f) which is a bit too much for my liking (we live in a cold climate). I'm using an arduino with DHT-22 to read the temp and an oil-fin heater on a mechanical relay for heating. I think the problem is the air temp rises quickly as soon as the heater is on but not the brew, so the relay shuts off before any ambient heat transfers to the brew.

So today I had a DS18B20 liquid temp sensor arrive, which is now mounted in the brew. Hopefully this gives better readings than the DHT-22 or the stick-on thermometer.

I also have a 30W heat belt coming on the courier, I figure this will be more efficient for heating the brew than a room heater and a lot easier to control.

I'm thinking I also need to add some form of cooling to this. A fridge isn't an option for me, but what about a 12v server fan or 2 aimed at the ferm? So my arduino would be activating the relay/heat belt if it's too cold or activating the fan if too hot. Maybe wrap some towels over the ferm at night since the temp drops a lot at night.

Does this approach sound ok? Anything else I need to be mindful of here?

Thanks in advance.

A fan won't cool your beer. It is only blowing ambient air which the vessel is already exposed to. Now it were wrapped in a wet cloth in a dry environment, the evaporation would cool the vessel a few degrees, but that is not easy to manage. You need a fridge.

Hi, thanks for the advice. A fridge isn't really an option (wife factor). But I have some cooler places I can put the fermentor which might help, or possibly duct some air from somewhere cooler with a fan.

Just looking at what other people do, a fridge would be nice but I need to explore other options.

You could always do a Son of a Fermentation Chiller if a fridge is not in the works. Here is a website that explains is all: http://www.ihomebrewsolutions.com.p.../wp-content/uploads/2012/10/chiller-plans.pdf

Hope this helps.

Or have a look at brewjacket.com

Cool thanks. I like that idea, and changing out ice every couple of days isn't a big problem.

A swamp cooler works very well. Get a large plastic tub (like the kind you see for backyard beer parties) fill with chilled water to match the level in your fermenter and swap out 1 liter frozen bottles of water. Should help keep the temperature down to the 64*F range. You can add more water bottles as needed. I think I paid $6US for my bucket at Target.