
There is a simple cheap solution. You need to buy a brew belt (heating element), an aquarium thermostat and a vivarium or aquarium stick-on thermometer. First stick the thermometer on to your fermenting bucket - this will provide your visual and accurate check on the temperature. Then set the aquarium thermostat to the right temperature (this will be approximate, but you can tune it with the thermometer). Now plug the brew belt into the thermostat and wrap it round your fermenter. Steralise the thermostats sensor (long bit of wire) and drop it into your brew so it sits in the middle about half way down in depth. Your brew will now be kept at a constant temperature, whenever it cools below what you have set on the thermostat it will be heated back up by the brew belt. The total cost of this equipment is about £20-£30 and is worth it's weight in gold!