It seems like often times home brewers place a ton of attention of the brewing process and not enough on the fermentation process. The truth is that both are critical to making a good beer. Brewing yeast is highly temperamental and is heavily impacted by temperature. If the temperature is too cold it begins to shut down, slowing replication and fermentation. If this happen at the wrong time in the fermentation process you will wind up with a sweet and under fermented beer and potentially bottle bombs. If your temp gets too high high you may flash ferment your beer ending up with a bunch of off flavors created by your yeast. What you want in a nice consistent temperature, specific to your lager or all yeast strain. A temperature that is consistent 24 hours a day, not fluctuating wildly day and night. For most ale yeast strains you are looking for a target temp of about 68 F. Depending on where you live, what time of the year it is and what type of equipment you have available will determine how you want to handle controlling your fermentation temperate. In any case, you are probably going to want to purchase a temperature controller such as the Ranco Digital Temperature Controller pictured above. I have used both Ranco and Johnson controllers and would recommend either; the Ranco just tends to be a little less expensive. In an ideal situation you would hook the temperature controller to a chest freezer or refrigerator to help insulate the beer from the elements.
If you are looking for a digital temperature controller for your home brewing fermentation, MoreBeer currently has the Ranco on sale for $83.95 and is Available Here
Recently I decided that I would create a temperature controlled RIMS systems for my home brewery. I picked up a Ranco Digital Temperature Controller (model # ETC-111000-000) to manage the temperature regulation. I have not quite completed the entire Recirculating Infusion Mash System, but I just wrapped up the Ranco wiring and thought that I would share what I learned in case it will help out anyone else.
The RIMS heating element that I am using is a stainless steel 120v heating bar, so I have configured the Ranco for 120, but the Ranco thermostat is also capable of handling 240v; it just requires a slight wiring modification. I would like to point out that I am not a professional electrician. Electricity can be extremely dangerous to work with and may result in death. You should always consult with a professional electrician when attempting a project such as this. Manufacturer hardware designs sometimes change and you should refer to your instructions prior to beginning. Here is a wiring diagram that I used for my Ranco Temperature Controller.
Ranco Digital Temperature Controller Wiring Diagram
I cut apart a heavy gauge extension cord to use for my wall power connection and for the wiring I used to connect to my output plug. Inside the extension cord is a ground wire, common wire and hot wire. In the diagram above I use the green wire to represent ground, the white wire to represent common and the dark red wire to represent hot. Please be aware that different cables use different colored wire to represent different things, these colors are just meant to be an example. I ran the grounding cable from my extension cord directly to my output plug ground connection and also grounded it to the metal case that I am using to house my Ranco temperature controller, plug and switches. I spliced the white common cable from the extension cord and connected it to the “COM” port on my Ranco and ran an extension wire to the common connection point on my output plug. Since the RIMS heating element that I am using is 120v, I ran the hot wire from my extension cord to the Ranco “120” port. I then connected a small length of heavy gauge wire from the “120” port on the Ranco to the “C” port on the Ranco Temperature Controller. Lastly, I ran a segment of red wire from the Ranco “NO” port to the hot wire connection on my output plug. I reviewed my work to make sure that all of the wires were connected properly and there was no bare wire exposed. I then connected the device to a GFCI outlet and tested the device with a voltage meter to make sure that everything was working as intended. The Ranco is great because you can select whether you want the power to activate when the temperature drops below a certain point or rises above a certain point which means that it can be used for either a RIMS type device or to control the fermentation temperature in a freezer or refrigerator without having to rewire the device or modify the hardware.
Ranco 120v Thermostat
If you are not comfortable doing electrical work or if you would prefer to avoid the hassle, you can purchase a wired Ranco Digital Temperature controller. You can find several different options available here at a great price via the link below. They also have spare temperature probes and mounting brackets for the Ranco available if needed.