Brewing Beer with a Sous Vide Cooker

[Ken] found an interesting use for his sous vide cooker. He’s been using it to help him with his home brewing. It’s unlikely that the manufacturer ever intended it to be used in this manner, but as hackers we don’t really care about warranties.

Beer brewing is as much of an art as it is a science. There are a lot of variables that go into the process, and tweaking any one of them can result in your beer tasting different. There is one process during brewing that is called mashing. Mashing is when you soak malted grains in hot water to pull out the sugar. The amount of sugar that gets extracted is very dependent on how long the grains are soaked, and the temperature of the water. If you want your beer to taste a certain way, then you want to ensure that the water stays at constant, repeatable temperature.

As a home brewer, [Ken] has been using his stove top to heat the water. This gets the water warm, but in order to keep the temperature consistent, he has to constantly monitor the temperature and adjust the knob accordingly. Who wants to sit around and do that all day? He needed something to control the temperature automatically. Enter the sous vide cooker.

Sous vide is a method of cooking in which food is placed into an airtight bag and then submerged in a water bath with very strict temperature control. The process takes a long time to cook the food, but the result is supposed to be meat that is cooked perfectly even while also retaining all of the moisture and juices. [Ken] figured he might be able to use a sous vide cooker to control the temperature of the mash instead of a water bath.

His experiment worked wonderfully. He used the stove top to help get the mash up to the close temperature, then the sous vide cooker was used to fine tune things from there. [Ken] says he was able to achieve 75% efficiency with his mash, which is exactly what he was going for.

17 thoughts on “Brewing Beer with a Sous Vide Cooker

  1. As a self confessed beer geek I would like make a small correction to your narrative. The mashing process is about conversion of the starches in the malt into sugars. The temperature of the mash aids the naturally occurring enzymes in the malt in the conversion process and the precise temperature used determines which enzymes are favored and what type of sugars the starch is converted into. Great use of already existing equipment!

  2. Seems like a great idea (if you’ve got the heater unit handy). I think I’d be looking at some screen to keep the bag away from the impeller and maybe a little durable insulation to slap on after the initial heating step to keep the heater duty-cycle small.

    1. Thanks. Keeping the bag out of the impeller was definitely the most annoying thing with this set up, so that’s first on my list of future improvements. When that problem is solved I’m going to look at some kind of lid that will still allow the sous vide to remain mounted on the pot.

  3. Just a thought, what is the ideal temperature for “mashing”? If the temperature is low enough why not use aquarium heaters, they’re cheaper than a sous-vide machine and the heater never comes in contact with the mash, of course agitation is another matter.

    1. First of all there can be at least 3 different temperature stages depending on what type of mash you’re doing. so there’s no one ideal temperature. Secondly, the temps are usually above 100F for the stages so you’re probably not gonna get that out of an aquarium heater without mods. Good idea though.

    2. 142-157F for malts. You can get more efficiency under certain circumstances by doing protein rests at lower (113, 130-140F) temperatures. Lots of people have used Hot water heater elements and a range of PID controllers (or just a rough PWM set, w/ user oversight)

  4. I did this years ago. I use one of those electric turkey roasters with a PID. I use the same roaster to roast my grains to make my own crystal/caramel malts and the like. If you buy grain in bulk you will save a ton of $$$ and get crazy flavor out of them.

  5. I went the other way- I turned my kettle into a sous vide machine by adding a hot water heater element to it and then hooking that up to a temperature controller based off of arduino. A much cheaper way to do it IMHO and the heating element also acts a boil assist.

    1. I’ve often thought about hooking up a servo to the stove knob so I could just use the stove itself to heat the mash, but I haven’t gotten around to actually implementing it yet. I guess in that case I’d still need something to circulate the wort in the pot. What do you use to circulate? Or do you just stir?

      1. I think a servo to a stove knob is way overcomplicating the problem… and you may also encounter the problem that sometimes even keeping the stove on its lowest setting doesn’t allow you to hold temperature- it just steadily marches up.

        I find that the heating element itself, since it heats the water in a relatively localized area, produces a fairly decent amount of circulation in the pot. I usually do a bit of stirring though as well, though I could also use my stir plate for this as well.

    2. I went even a different direction – added sous vide capability right into the stovetop :-) Basically, I spliced a beefy solid-state relay in series with the big burner I do my beer boils on, with a bypass switch in parallel for normal operation. This allows using my same old stove and any cookware as usual. All the guts (SSR, bypass switch, phono jack for PID controller input) are either hidden inside the stovetop or recessed under the lip, so it looks unmodified unless you’re really looking for it. More details about my setup at http://tim.cexx.org/?p=1092

  6. Interesting. When I tested this method – virtually identical to what you show, I managed to burn wort on to the element which left a harsh taste behind. It also was a bit hard to clean off the heating element.

    I mashed in at 152F when the circulator reached that temp – it did hold the temperature really steady but the grain bag restricts circulation if you are not careful, which is what I think caused the scortching.

    1. I don’t understand, the element is physically similar to the Tractor Supply bucket heater I use with my ghetto RIMS system. Electric kettles boil the wort and don’t scorch. Why would this one be different unless it doesn’t shut down at high temp (which without looking at the manual I’m pretty sure it does)?
      I have to give this a try, have some ideas. Beersmith here I come!

  7. I built my sous vide machine from a large rice cooker, a cut off switch connected to an electric thermometer and it’s worked great for food.

    It’s a big rice cooker, so I imagine it will be perfect for my attempt to get a mash going in it.

    Best part is that a rice cooker heats from the outside and it has nothing to interfere with your items on the inside, and has a Teflon coating – so nothing will stick and it will always be easy to have it clean and sanitised.

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