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ThermoStar® Two-Way Digital Temperature Controller

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ThermoStar® Two-Way Digital Temperature Controller

SKU: U41264

The first digital temperature controller designed to automatically switch from hot to cold with the push of a button, for groundbreaking flexibility and ease-of-use in perfecting homebrew fermentations.

From: $84.99

To: $116.98

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ThermoStar Digital Temperature Controller   ($84.99)

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The first dual-mode digital temperature controller to go from -50°F to 300°F—and back again—with the flip of a switch. Forget the Ready, its low-profile, ultra-mountable design is Set and Go. With a responsive dual-color LED display and modular probe that eliminates the need for a thermowell, perfect homebrew has never been so effortless.

No longer is an advanced degree in electrical engineering required to achieve flexibility in fermentation temperature control. ThermoStar® is the only temperature controller that you'll never need to disassemble or re-wire for perfect performance. With ThermoStar®, switching from heating to cooling is not only easier than ever with the simple push of a button, it is instantly recognizable with an LED screen that displays the target temperature in blue when the unit is in cooling mode and red when it is in heating mode.

A low-profile design outfitted with multiple mounting options—everything from magnetic to suction to nail hooks—ThermoStar® delivers superb, reliable control even in the smallest of fermentation spaces.

Upgrade the modular stainless steel probe to our longer 12” model and monitor the actual internal fermentation temperature of your wort without the need for a thermowell.
Details & Instructions

Additional Information

4.4 / 5.0
21 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Nice Unit
I bought this when they offered a free 12" probe with purchase. The setup with a 12" probe works really good in my better bottle using a standard carboy cap. The only issue I had was with the original settings. The directions indicate that the temperature differential factory setting was 2, however, my unit was set at 3.7 degrees. Fortunately I was around for the day during my initial test, so I caught it and was able to change it to 2. I am currently fermenting an IPA in a 50 degree room, using the temp controller with a heat belt. I set the temp at 68 and it kicks the heat back on when it drops to 66. Very happy with this unit.
December 10, 2014
Thermostar Digital Controller
Great addition to the arsenal of homebrew equipment. Brewing in the heat of the Florida Keys provides numerous challenges (e.g., cooling water, fermentation, bugs flying into wort) and perhaps the largest was fermenting anywhere near optimal temperatures. With the help of a retired chest freezer and the Thermostar I have been able to make a couple of batches of ales where you can really taste the difference that fermenting at 65 versus room temperature (77) makes. I currently have an Octoberfest lager in its second month of cold fermenting (37 degrees), something that, down here, would be impossible without temperature control. Awesome product for a world without basements or seasons to help regulate the ambient air temperature.
August 4, 2016
I brew in my basement which is very cold during winter months and was affecting my ale fermentation. The ThermoStar has elevated that issue.
February 25, 2016
Poor quality
This worked fine for about a year. Then one day the display started flashing and would not function. Shortly thereafter, it wouldn't come on at all. Completely dead. I emailed for advise, but apparently nothing could be done... Gonna give the MKII a try, it seems to get pretty good reviews.
May 30, 2017
Easy to use
Does the job and keeps the heat in the area you need once you do some research and find out the temp drop range before it activates again. The Midwest directions were perfect.
March 10, 2017
1 year ago
Works Great!
In the past I've used the analog Johnson control, but this controller is well worth the extra money. I've paired it with a chest freezer and have loved the results. My Johnson never seems to keep the correct temp, but the Thermostar holds the temp within a few degrees consistently. Add in the ability to switch to a heater and I can use it to keep an area warm on those cold winter nights. Works great!
August 12, 2014
Great Product
Make sure to check your settings. My default was plus or minus 3.7 degrees. Easy enough to change. I have a Johnson controller on my keezer and got this to try out on my fermentation chamber. So far I like it much better. It is very easy to change into heating mode, it has a great display, the modular probe is great, and it has a built in magnet that sticks right to the fridge. No complaints so far. 5 stars.
January 18, 2015
Working fine
This unit seems to be working fine after 1 months use. Easy to install and adjust. It appears to hold temp on a converted chest freezer to +/- 3 degrees or so. Easy to install, but the magnetic backing is not very strong. It doesn't hold the unit to the side of the freezer and after an hour or so it slowly slides to the bottom. The was fixed by placing a piece if double sided tape on it.
May 24, 2017
1 year ago
Great Product and so Simple to Use
Plug and play is no joke! This is one of the best piece of homebrew equipment I've bought. It's slightly more expensive than a few other temperature controllers, but it's worth every penny. Do the research and come back here to buy it.
March 8, 2017
1 year ago
Fermentation - simplified
I purchased this when my basement became too warm to do fermentations during the summer. This kept my fermentation temps in check and the batch turned out great because of it!
July 6, 2017
1 year ago
Customer Q&A
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Browse 8 questions Browse 8 questions and 24 answers
What has been used with the ThermoStar Digital Unit for chilling?
A shopper on Feb 10, 2017
ThermoStar® Two-Way Digital Temperature Controller
ThermoStar® Two-Way Digital Temperature Controller
ThermoStar® 12
ThermoStar® 12" Stainless Steel Temperature Sensor
BEST ANSWER: I use the 12" sensor through the airlock hole on top of both a 6 gallon bucket and a wide mouth carboy. Alternativley you can tape the shorter sensor that comes with the unit to the side of the bucket or carboy and that works well also.
What has been used with the ThermoStar Digital Unit for chilling?
Matthew S on Feb 10, 2017
ThermoStar® Two-Way Digital Temperature Controller
ThermoStar® Two-Way Digital Temperature Controller
ThermoStar® 12
ThermoStar® 12" Stainless Steel Temperature Sensor
BEST ANSWER: I have a 5 cubic foot deep freeze that I use for a fermentation chamber. I set the freezer's dial at the lowest setting and plug it in to the thermostar as per the directions. I have a drilled stopper with two holes. One for a airlock/blow off tube, the other I slide the 12" probe into. This allows the thermostar to turn the freezer on and off as needed to keep the brew at the correct temperature I set. It's better to use the temp of the wort vs the ambient temp because they can vary by quite a few degrees as fermentation takes place. The simple plug in style of the 12" probe is a no brainier for sure and I was able to easily maintain my temp within a degree or so even in my garage in the middle of summer in 29 palms California.
does this unit automatically control the temp between heating and cooling or every time i want to cool i have to switch it to cooling and vice versa? In other words i want to set it and forget it without toggling switches
A shopper on Feb 19, 2018
BEST ANSWER: You have to switch it. Think about it though, if it was automatic you would have to have a heating pad inside your refrigerator for it to work. The ambient temperature that you are trying to rise above or below will bring it back to the temp you set it at ... Unless you live is some alternate universe!
My Thermostar Controller is flashing temperatures between ambient and zero. It does not matter which setting (cool, off, heat) is selected the controller appears to work for about 10 minutes before the fluctuating reading startup. Has anyone seen this problem? My unit is 15 months old and never given me issues before. Thank you.
A shopper on Feb 20, 2017
BEST ANSWER: I've not had this issue, but it almost sounds like when the unit is warmed up (powered on for 10+ minutes) that's when the issues start. I suggest making sure that the connections are clean to power cord and between the sensor cord and the control unit. Other than that I suggest contacting the manufacturer regarding the issue. Good Luck.
Would this work on an electric smoker?
A shopper on Dec 17, 2016
BEST ANSWER: It really depends on what type of electric smoker you have. This control module turns the power on and off to whatever accessory is plugged into it, according to the temperature needs. So, if your smoker runs on continuous power and doesn't need to be programmed every time that it powers off, I would think you would be good to go. Just make sure the module's upper limits will work with whatever temp you like to smoke at too.
My Thermostar won't turn off the freezer. It reads the temperature accurately enough but the switch never turns off. So I end up with a lot of frozen wort. Since it's reading the temperature correctly I don't think replacing the probe would help. Is there anything I can do to fix this unit or is it a paper weight now?
A shopper on Dec 11, 2017

I'm sorry to hear about the problems with the Thermostar. This may be best to reach out to our Customer Service team to help with. Our phone number is 888-449-2739 or feel free to email us at
To follow up to the answer of Rob's question, will this work in a 6 gallon carboy if I get a solid stopper and drill it to the proper size to insert the probe and wire?
M A on Sep 11, 2016
BEST ANSWER: Yes, that would be fine to do, as long as only the probe is in the liquid. The long probe is of course best for this use. -Mike W, Midwest Supplies
Can I order the original temp probe it comes with?
D A on May 28, 2016
BEST ANSWER: Unfortunately, we do not sell the standard probes by themselves

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