Craft The Perfect Draft - Control Your Temperature

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When I look back and think about all the hours I've spent reading about beer brewing over the years I can't believe there's still something out there that I haven't tried incorporating into my brewing process yet. One year my push was into brewing all grain, one year was all about yeast propagation and pitching rates and another year had everything to do about brewing water chemistry. Why would I ever have waited so long to take control over my fermentation temperatures, I'll probably never know. What I do know is that I seem to have saved the best for last, I haven't been this excited over a new piece of brewing gear in a very long time. Maybe it's because I was passionate about computers, programming and electronic circuitry long before I ever thought about brewing beer but the ability to maintain precise temperature control throughout the entire fermentation process eliminated one of the last remaining variables in my brewing process.

What sets the STC-1000+ controller apart from other 'off the shelf' controllers is alphaomega's updated v1.06 firmware and the new functionality that it adds to an otherwise ordinary controller. The firmware ties the controller's hardware components together to deliver precision temperature control to separate heating and cooling outlets that can be used to maintain perfect fermentation temperatures. At the heart of every BrewsBySmith Fermentation Kit is the ubiquitous STC-1000 controller that's already been upgraded to a STC-1000+ with alphaomega's v1.06 firmware, a temperature probe, stainless steel thermowell, two square feet of 32 watt Fermwrap and a stopper that accepts both the thermowell and an airlock. Pretty much everything needed is included in the kit to add precision temperature control to any fermentation chamber, refrigerator or freezer.

I was able to order my Fermentation Kit with an optional tricolored LED light that turns blue or red when the cooling or heating outlets are on and with my very own customized nameplate. Both extras add a little more to the cost of the basic kit, and I know they fall into the 'bells and whistles' category, but I definitely think they're worth having. After unpacking and plugging the controller into a wall outlet I was ready to use the front panel buttons to quickly configure the basic settings needed to ferment my beer at a constant 70F temperature.
To configure the STC-1000+ to run in basic thermostat mode press the 'S' button once to enter the menu and then press the 'Up/Down' buttons until 'SEt' is displayed.
With 'SEt' displayed press the 'S' button then use the 'Up/Down' buttons to scroll through the sub menus until 'rn' is displayed, which is the run mode setting. Press the 'S' button again and use the 'Up/Down' buttons set the display to read 'th', which is the thermostat setting, then press the 'S' button to save the change. Press the 'Cancel' button to return the 'SEt' menu. This will program the STC-1000+ to run in thermostat mode
With 'SEt' displayed press the 'S' button again until 'SP' is displayed then press it again to set the temperature set point. Use the 'Up/Down' buttons to increase or decrease the set point value until it matches your optimum fermentation temperature. Press the 'S' button to save the change then press the 'Cancel' button to return the 'SEt' menu. This will program the STC-1000+ controller's temperature set point.

With 'SEt' displayed press the 'S' button until 'hY' is displayed, press it again and use the 'Up/Down' buttons to change the hysteresis value. This will limit the range away from the temperature set point, in either direction, where both outlets will be turned off. Press the 'S' button to save the change.
Example: Setting the 'hY' value to 1 will turn the heat outlet on when the temperature drops more than 1 degree below the set point, or turn on the cold outlet on when the temperature rises more than 1 degree above the set point.
With 'SEt' displayed press the 'S' button until 'hd' is displayed, press it again and use the 'Up/Down' buttons to change the heating delay value in minutes. Press the 'S' button to save the change then press the 'Cancel' button to return the 'SEt' menu. This setting will delay the heating outlet from turning on again within this time period.
With 'SEt' displayed press the 'S' button until 'cd' is displayed, press it again and use the 'Up/Down' buttons to change the cooling delay value in minutes. Press the 'S' button to save the change then press the 'Cancel' button to return the 'SEt' menu. This setting will delay the cooling outlet from turning on again within this time period.
I checked my settings to make sure that 'rP' ramping was disabled, the 'SA' set point alarm was off and the 'tc' temperature correction was set to zero. Once the controller was programmed all that was left to do was mount the number 6 stopper in the lid of my fermentor, push the thermowell and air lock into it and feed the temperature probe down to the bottom of the thermowell. For the very first time since I began fermenting my own beer I felt like I had complete control over my fermentation temperatures. The controller was able to maintain a consistent fermentation temperature in an unheated garage for the next two weeks as the outdoor temperatures dipped into the low to mid twenties.
Judging from all the positive feedback I've gotten from the people who've tasted some it appears I've done something right, everyone including myself really enjoyed drinking my first Belgian Witbier fermented under such favorable conditions. Although I built my own makeshift heater made out of an inexpensive clamp light, a 100 watt bulb, some aluminum flashing and some duct tape I already have a few tweaks in mind before fermenting my next batch of beer. I plan to lay the FermWrap on the bottom of the chamber and sit the fermentors on top of it while also using a modified version of my paint can heater. The next heater build will use pop rivets instead of duct tape for a more permanent build and have a smaller diameter so it fits easily between my two fermentors to evenly distribute the heat and avoid hot spots. If you've tried just about everything to brew the best tasting beer possible and you feel like the beer's still coming up a little short on flavor you may want to do like I did to control your temperature.

Vince Feminella [aka: ScrewyBrewer]
[email protected]
Very informative post! However, I just don't see why it is necessary or practical to have dual-stage temperature control (vs. single stage) with a temperature probe stuck down in the middle of your brew. I would guess that with this sort of set-up your heating and cooling elements are constantly turning on and off - counteracting the effect of the other which likely overshoots each and every time since your liquid reacts slowly to changes in ambient temperature. Do you see this in your set-up?
@masaba that's were the benefits of the STC-1000+ comes in handy, overshoot and chatter between the cold/hot is easily controlled using the 'delay' and 'hysteresis' settings. Together they work like a gas pedal of a car to let you smoothly apply just enough heating or cooling to maintain the setpoint temperature without a lot of overshoot.
@masaba You can set the sensitivity such that this isn't an issue. The beer is a pretty big heat sink, and in a .5 degree range when measuring beer temp (not ambient) this does not happen in my experience.
Great article. I recently did a similar upgrade, except I am using the Auberns TD100A It's a dual-stage controller that has some nice features. So far I've been able to keep my first attempt within about a degree of my setpoint, but I did experience some swings as I learned how to set it up. I'm still working some layout refinement in my mini fridge. There is a lot of stuff in there now and i'm just working on how to best fit it all together.
Great picture of the thermowell setup. I'll have to purchase one of those. Currently I have the RTD taped to the Carboy wall with some foam insulation covering it.
You stated you were going to set your carboy on top of the fermawrap heater? Currently I have a carboy carrier. I'm curious what the best way to apply the heater would be. Should I slide it in between the carrier and the glass or just tape it on the outside of the carrier? If you set your fermenter on top, you might want to take some sand paper and smooth out the sharp edges of your bucket (if that's what your using) They tend to get burrs from dragging and moving that could damage your FermWrap.
Thanks again for posting an informative article,
Awesome article! Thanks a lot for sharing!
And as always the STC-1000+ project can be found at https://github.com/matsstaff/stc1000p
I have a chest freezer with a stc1000, for heat I use a ceramic infared heater. They screw into a lightbulb socket and emit no light
Great article Vince.
You were a big influence to push me way outside the box in my MrBeer days.
I Have a few questions?
1st I don't see the point of adding the temp probe into the beer its self? what if you had more then one beer in at a time? I know it would probably be the same temp in each one but that's just another thing to stick into clean beer. why not just use a glass of water in there?
2nd is there any concern in using light bulbs inside for up to a month depending on how long you ferment?. In a clear carboy at that?
and I guess I have 3 questions. Do you need a 2 stage? the problem I have is keeping it warm in the winter and cold in the summer.
@Inkleg thanks for posting Jeff, I'm happy to see that you're still passionate about brewing these days too! Back in the Mr. Beer days, same as today, we all benefited from what the more experienced brewers had to share with us.
1. No, you don't need to put the probe in the beer, but you want to measure the temp of the beer (and not a glass of water), taping the probe to the side of the fermentor and adding some insulation is the usual compromise (and it works very well).
2. I personally don't like bulbs for heaters, but because of safety. The light might affect the beer, but mainly bulbs can get hot and most will provide more heat than necessary.
3. What about spring and autumn? And when you want to have a temperature profile (diacetyl rest, cold crash etc). A dual stage controller allows you to to do all that no matter what the ambient temperature is currently. So no, you don't need a dual stage thermostat, but you want one :)
I brew small batches in Florida, and I'm planning on using a mini fridge as a ferm chamber. Would the STC-1000 be a good investment for that? I don't think I would need a heater down here, right?
I'm partial towards stc-1000+ (ie an stc-1000 with the stc-1000+ firmware) as it has some nice features for fermentation (like profiles). But if all you want is a thermostat to manage cooling and reads in fahrenheit, there are single stage units like the willhi availiable.
I guess I Understand, see I just put a light bulb in the late fall, winter, and early spring. and just let the fridge run during summer late fall. So my way sucks because I turn down the fridge and turn the light on, so at times they are both on vs. each other.
I still like to do multiple beers at once in different stages. Would it be possible to do that.
For multiple beers you'd need multiple controllers. Now, I haven't done this myself, but using one fermwrap or similar per beer should be viable. You could probably still use the fridge thermostat to manage the fridge temp, as long as it is set below the lowest desired fermentation temp.
I would think if you have all your different beers fermenting in one dark room, you wouldn't need multiple thermostats per beer. Have you looked into flex watt heat tape? My wife and I used to breed reptiles and we used flex watt heat tape with one thermostat to heat three separate rows of reptiles. The heat tape is great because its easy to use and its max temp on it is 90 degrees. As long as you dont set it on carpet, and use some adhesive risers to place on the bottom of your fermenter you will have a little room to let the heat disperse.
@timmustang I'll admit it does make sense as long as the wort gravity and yeast strains are fairly close in nature between the different beers. I would expect that a low gravity beer pitched with a fast fermenting yeast will produce a different internal temperature profile than a high gravity beer fermented with a lower attenuating strain. But all things being equal having a room full of fermenting beer would simplify fermentation considerably.
I got one of these kits for Christmas and I'm trying to brew a hard cider with it. I want it to get up to about 70F, but every time I get it up there (I have a heating belt to heat it with) it chills it back down to 65. How do I fix that? I have my STC set to 70F, and the Hysteresis is set for like 2 degrees.
What am I doing wrong???
Oops. Re-reading the instructions it looks like I may have left out a step to adjust the cooling settings. I'll re-read that when I get home. :)