Brewers Choice Brewing Thermostat

USING A BREWING THERMOSTAT
The number one reason for using a Brewing thermostat is better-tasting beer. Using a Brewing thermostat goes hand in hand with using beer yeasts at the correct temperatures (See Using SAF Yeasts). Maintaining the correct temperature for the yeast strain being used during fermentation
equals better beer.
Yeast is a living organism and needs to be treated well to give a good result. This generally means keeping the beer cooler rather than warmer during fermentation. Unfortunately, a lot of the information provided by manufacturers of beer kits over many years advised brewers to ferment their beers at a warm temperature (sometimes up to 30 deg). As a result, many brewers always keep the fermenting beer warm. However, this does not make great beer.

If you use the yeast included in the beer kit, a much better result will be achieved if the beer is fermented below 25ºC. Although the yeast will work at higher temperatures and brew much faster, the resulting flavours in the finished beer will suffer. The higher the fermentation temperature, the more by-products are produced in the beer. These by-products are generally the flavours that are associated with “THAT HOMEBREW TASTE”. Brew at a lower temperature and get a better beer straight away.
If you can control the temperature during fermentation, it then becomes possible to high quality yeasts at the correct temperatures. As a general rule, a genuine Lager yeast (Saflager S23, W34/70) gives the best result if fermented at around12ºC. Quality Ale yeasts (Safale S04, US56, WB-06) give the best result fermented at around 18-20ºC. At these temperatures there are little (If any) unwanted flavours being produced, resulting in a better tasting beer.
The correct fermenting temperature is one of the most important things (second only to proper sanitation) to produce good quality, clean tasting beer. Using a Brewing Thermostat with a fridge or freezer allows you to easily regulate the temperature inside the fridge to give the best results all year round for the yeast strain being used.
Using a Brewing Thermostat and fridge
A Brewing Thermostat is used with a fridge/freezer to easily control fermentation temperatures.

Installation is very simple. Set your fridge /freezer to its coldest setting. The Brewing Thermostat is plugged into the power point and the fridge/freezer is plugged into the back of the Brewing Thermostat. The wire temperature sensor is placed inside the fridge/freezer. Make sure that the sensor is not touching the floor or wall of the fridge/freezer. If the fridge has a separate freezer compartment, make sure the sensor goes in the fridge area (the area where your fermenter will be).
The temperature inside the fridge is now controlled by setting the dial on the Brewing Thermostat. Place your fermenter in the fridge and adjust the dial on the Brewing Thermostat to the appropriate temperature. The required temperature will depend on the type of yeast being used and the temperature of the wort in the fermenter. There are many variables and each situation will be different. 
As a general rule, a genuine Lager yeast (Saflager S23) gives the best result fermented at around 12ºC and quality Ale yeast (Safale S04, Safale US56) gives the best result fermented at around 18-20ºC.
Ideally, the yeast will have been pitched when the wort is at the same temperature as the optimum fermentation temperature for the yeast being used. You can simply set the temperature on the Brewing Thermostat to the fermentation temperature and let it go. However, the action of the yeast in the fermenter will generally create a little heat in the fridge and a slightly lower temperature should be set on the Brewing Thermostat. This is normally a degree or two lower than the required fermentation temperature. This is especially necessary if there are 2 or more fermenters in the fridge. It is not a perfect science, every fridge is different and requires a little bit of trial and error
to get it right.