The Benefits of Temperature Control

Posted on 07.26.08 5:19PM under Brewing

Friday was the Fermentation Friday, with the topic “Advice for Brand New Homebrewers”. I came up with “Start Simple”, advising just to get started with the most basic equipment, and let experience be your guide. But I can’t resist expanding on that for folks that have brewed a few batches and are looking for process improvements.

There are so many factors that go into making beer and so many process changes I’ve made along the way that it’s hard to pick one and recommend it as the ultimate. And of course, I’m still working on perfecting my technique to get exactly the results I want. In a way I don’t think I’ve found the silver bullet for slaying the werewolf of imperfect homebrew quite yet.

I can’t say enough about the awesome power of fermentation temperature control.

Of all the things I’ve done to try to get my beer making where I want it to be, nothing gives me the peace of mind that having a digital temperature controller connected to an old fridge gives me. The ability to heat the space with a 25 watt heating pad and cool it using the built-in function of the fridge gives me the ultimate control over my fermentation schedule.

This means no more worrying about the temperature in the basement or the temperature in the closet, or any other factors outside my control. I have complete control over the temperature, and thus complete control over my yeast and the beer that they’ll make for me.

Without temperature control, the heat produced by yeast growth early in fermentation can get out of control. Before temp control, I routinely had beers fermenting in the upper 70’s. Now it’s a cool 66 all the way.
Uncontrolled beer gains a lot of heat in fermentation, and then when activity slows, the temperature can experience a dramatic drop. I had a lot of beers with high finishing gravities before I had temperature control. I believe this was due in part to the temperature crash the fermenting beer experienced when the yeast stopped making so much heat.

Since I’ve installed temperature control, I get predictable finishing gravities.

I am a computer programmer. As such, I expect to work in a certain controlled temperature environment. I work best when it’s pretty cool, in the upper 60’s, not unlike our single-celled friends called yeast. At my work, it’s as hot inside as it is outside. That means I’m writing code at 90 degrees with full summer humidity. Let me tell you, under these adverse conditions, it’s hard to focus on your work. Imagine how the simple yeast feel when forced to work under these conditions. And we don’t even pay them! They just all end up dead at the bottom of the bucket. At least I get to go home and have a beer at night after work.

So in conclusion, get fermentation temperature control, and rest easy. You will gain complete control over the part of the process that is subject to the greatest variation. Controlling brew day variability is possible with the basic equipment that’s required to make beer in the first place. The temperature controller and used fridge are the best next step you can take to gain control over the outcome of your brewing.

Read Comments

  1. Posted by E.S. Delia on 07.27.08 5:56 pm

    See, even as a novice, I’m already wanting to be a master of the surroundings when it comes to brewing. What kills me is that I’d love to make a doppelbock or altbier, but not being able to ferment at cooler temperatures is a problem. I can’t complain though, I’m fine doing different ales at the moment.

    It’d be nice to have a fridge solely devoted to fermenting (and hell, one for cellaring, too!). Perhaps in the future, these things will come. But for now, do you have any other recommendations or tricks of the trade for temperature control that don’t involve another fridge unit?

  2. Posted by Keith Brainard on 07.27.08 6:35 pm

    I have heard of people using what’s called “Swamp Coolers” where they put the fermenting bucket in a bigger vessel full of water. The water helps to add thermal mass, and allows you to control the temperature that way. You can cool that water with ice packs if you needed to. You could probably come up with a way to heat that swamp cooler water, too.

    Another trick is to use a wet towel on the fermenter. The water in the towel will evaporate, which serves to remove heat from the fermenter.

    Before I had a fridge with a temperature controller, I covered my fermenter with a cardboard box, and tried using frozen water bottles to keep the temperature under control. I’m not sure this was ever that effective, though.

  3. Posted by E.S. Delia on 07.28.08 7:43 am

    Oh wow, I would’ve never thought about the towel-evaporation trick, but it certainly makes sense. That could come in handy for future batches. And the swamp cooler may be worth looking into as well for better temp control. It’d definitely be ideal to have a climate-controlled fridge, though.

    Hopefully, if the need arises, I can employ some of these tricks. We had a scare regarding fermentation temperature with our Belgian Dubbel, but luckily all seems to have turned out well in the end.

  4. Posted by Keith Brainard on 07.28.08 7:37 pm

    It’s probably pretty safe to ferment a Dubbel warmer than normal, those Belgian yeast like it hot, right?

  5. Posted by Alan Whitley on 01.10.09 12:01 am

    I live in a subtropical climate (Queensland, Australia), so keeping the fermenter warm is not an issue, but achieving low ferment temperatures is a challenge, particularly with lager yeasts, where I’m aiming for 13 deg C ferment temps, but ambient conditions can be 28 deg C or higher.

    Water baths, wet towels, ice packs and fans just don’t cut it as they can’t shed enough heat, and I don’t have the space for an additional fridge.

    However, I have cracked it without refrigeration. I found a product called Techni Ice (http://www.techniice.com) that I use to create a ferment cooling blanket.

    These are gel/water sheets that have the cooling capacity of dry ice. I sewed up an old towel so that I formed 3 pockets, got some aluminium lined rubber foam insulation and cut to the same size as the Techniice sheets. I place 12 sheets of Techni ice in the freezer 2 days before starting a brew.

    I use water chilled in the fridge to get the correct pitching temperature. I then place the insulation in each pocket of the towel and 1, 2 or 3 Techni Ice sheets. I then wrap this around the fermenter and keep it tight with an elastic strap.

    If trying to hold temperature only (e.g. 21 deg C ferment in a 28 deg C ambient) I need 1 Techni Ice sheet.
    With 3 sheets I can drop the ferment temperature 2 deg C per day. Once target is reached I then regulate by using 3, 2, 1 or no Techni ice sheets depending on ambient conditions. I replace the sheets after approximately 24 hours when they have lost their cooling capacity.

    Whilst not thermostatically controlled, I can keep my 23 litre brew within +/- 1.5 deg C of my ferment target by intervening once per day.

    To make it clear what my gadget looks like, imagine a towel folded in half length ways to form a long pocket. Working from the outside in:
    -single layer of towel
    -insulation with rubber side facing out and aluminium side facing in
    - Techni ice sheet
    -layer of towel
    - plastic fermenter

    The Techni ice product really has amazing thermal properties, is reusable, and can also be used to heat (though I haven’t had a need to try this).

    Hope this of some use to those of you who don’t have refirgeration as an option.

  6. Posted by Bill Clark on 02.15.09 12:24 pm

    I too am a computer guy, and like to know that I am in control (smile)

    For 5 gallon pails, what sizr fridge ? Also – what controller do you like ? I am using a ranco in the chest freezer for the kegs .. seems to work fine.

  7. Posted by Keith Brainard on 02.15.09 2:37 pm

    I have a “standard” size old fridge, with the freezer on top and the fridge down below. I have no idea how big is actually is in cubic feet, without measuring it.

    I am using the Johnson Controls controller shown above in the post, and I like it. Looks pretty much the same as the Ranco. I just wish I could have a single controller that would control both heating and cooling elements.

    A chest freezer is a great option, I just happened across a neighbor that was getting rid of an old fridge as part of his kitchen remodel.

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