Like many homebrewers, I’m also an amateur chef. I recently purchased a sous vide device which is a trendy bit of gear that lets you cook food slowly and evenly in a hot water bath. It’s great for making lengua tacos, venison roast, and more, but it doesn’t take too much imagination to see how it could be a useful brewing tool. My first idea was to use it to keep the mash or kettle warm for a quick sour, but it was a short leap to realizing that I could brew a small all-grain batch with it.
The challenge with all-grain brewing is hitting and holding your mash temperature. The sous vide cooker solves both of those problems with a minimum of fuss. The only caveat is that it depends on having enough water present to circulate through the device, and you need to keep the grain from clogging it up. That makes it very well suited for no-sparge brew-in-a-bag (BIAB) brewing.
I’m pretty sure that my cooker could handle a full five-gallon batch, but I got more excited about doing smaller, proof of concept beers. Part of the rationale is that the grain bag is more manageable, but the ease of use is another strong factor. I’m more willing to experiment when I haven’t invested too much of an effort. As a test, I whipped together a three-gallon batch of smoked ale.
Most sous vide cookers are fairly similar. They’re self-contained, with a heating element, a temperature probe, and a circulating impeller, all within a protective housing.
You’ll also need a brew pot and nylon bag to hold the grain. If you’re already familiar with no-sparge BIAB brewing, you know you need to calculate your total volume of strike water to account for absorption, rinsing, and boil-time evaporation loss. For sous vide brewing, your brew pot geometry is also a factor. The water level for the grain and liquid will need to fall within the range that the sous vide cooker can handle. If level is too low, the heating element can be damaged, but if it’s too high, water may seep in where it’s not wanted.
In my case, I looked at a couple of different brew pots to see where the water level would end up. As it turned out, the water level was a bit too low in each of my pots. I solved this problem by putting a full gallon glass jug in the pot during the warm up phase. This took up enough space to raise the water level high enough to fall into range.
Sous Vide Mash Process
Sous vide brewing is remarkably simple. The bulk of the work is selecting the right brew kettle.
Calculate the strike water needed. This will be based on your desired pre-boil volume plus the water absorption of the grain (about 0.1 gallons per pound of grain). For my three-gallon batch, that ended up being 4.75 gallons: three gallons of wort, one gallon to evaporation, and three quarts for water absorption.
Choose the right brew pot. Add the water to your pot and mount the sous vide device. If the water level does not fall between the min and max lines on the cooker, try a different pot or, if necessary, add a spacer to the pot, such as a jug of water. Perform any necessary water chemistry adjustments, such as adding gypsum or calcium chloride Turn on the sous vide cooker and set it to your target mash temperature. While the water is heating up, grind your grain and place it into a nylon mesh bag. Once the water reaches your mash temperature, put the bag of grain into the pot. Stir the grain within the bag to break up any dry pockets. Once the mash is well stirred, let it sit for 60 minutes.
To mash out, change the sous vide temperature to 170 °F (77°C). It will probably take a good 10 minutes to heat up. Once it’s there, let it sit for another five minutes or so. Turn off the sous vide cooker Lift the bag out of the wort, letting it drain into the pot. Note that you shouldn’t squeeze the bag. Start your boil as usual.
Hot or Not?
My three-gallon batch of smoked ale went very smoothly. It wasn’t any quicker than a standard five-gallon batch, but it was much simpler. It was nice not to worry about hitting my mash temperature or about heat loss (especially for a small seven pound mash). Lately, I’ve been skipping the mash out step, but it was trivial to keep it in when it’s just a simple temperature reset on the sous vide cooker.
Final verdict: I wouldn’t buy a sous vide device just for brewing, but it’s a nice tool to take advantage of.