Fermenting with Sous Vide
By Thom Cannell
Finally, an easy method for delivering optimum fermentation temperature to a yeast that loves 90+°F temperatures. As a benefit, you can create great meals with this method, as well!
The journey began after reading a recipe for a one-week Märzen using the fast-fermenting Lutra strain of Kveik
. The grain bill was simple, the ABV modest and a beer drinkable in a week (according to the recipe), but there was something missing. How the heck to keep the fermenter at 90°F? (Or when making certain Belgian-style beers, Brett beers and sours at 75°-85°F?)
Personally, I’ve been brewing for several decades and have always struggled to keep fermentation temperature 65°-68°F for ales and much lower for the occasional lager. Most of us have used the “wet towel wrapped around the fermenter” trick, or a cold basement, and the very lucky have a dedicated chill-chest with temperature control. But keeping the wort warm? Some in my homebrew group have, in summer, simply fermented high-temperature beers in their garage or spare room. But that seems a bit sketchy as summer rolls into fall.
My first thought was a heat wrap
, the wrap-around-your-fermenter kind. I also thought about using a standard pharmacy-grade heating pad. But, how to control the applied temperature without a thermowell?
My next idea was to use a box with insulation, small electric heater and RANCO or Inkbird controller
, which I have several of. The box would be that which contained my new 30L Anvil Foundry
brewing system, its Styrofoam packing/insulation used for heat retention. It seemed a reasonable solution, and cheap. But how effective would it be?
Then, as I was cooking a chuck steak overnight in a Sous Vide water bath at 134°F, the solution struck me.
So, on brew day I dispensed my Märzen
wort into a stainless corny keg and sprinkled on Lutra dry yeast. The next step was even easier, placing the corny into a water bath, setting my Sous Vide
recirculating heater to 90°F and walking away. FYI, fermentation was complete in under 30 hours and the result is chilling as it force carbonates.
To date I’ve used this system only once and I suspect that a brew bucket could be used similarly and placed into a plastic tote. However, I have no clue about the duty cycle of maintaining a larger volume of water at temperature. Yet, as many sous vide recipes call for 24-36 hours of operation and a 65+°F temperature gradient (70° ambient and 124-165+°F water bath), it may not be a problem.
If you are unfamiliar with Sous Vide water bath cooking in the kitchen, from Wikipedia:
“Sous vide cooking is characterized by low-temperature cooking, a longer period of cooking than conventional cooking, a container (such as a plastic bag) that separates the food from its heating environment, and pressurized enclosure using full or partial vacuum. … Sealing the food in sturdy plastic bags retains juices and aroma that otherwise would be lost in the process. Placing the packaged food in a water bath, with the temperature set at the desired final cooking temperature of the food, prevents overcooking, because the food cannot get hotter than the bath it is in, as in bain-marie.
As a result of precise temperature control of the bath and the fact that the bath temperature is the same as the target cooking temperature, very precise control of cooking can be achieved. Additionally, temperature, and thus cooking, can be very even throughout the food in sous vide cooking, even with irregularly shaped and very thick items, given enough time.”
There is a limitation to sous vide when preparing most proteins; there is no surface browning or charring and your steak will be ugly. Sous vide directions typically advise, for most proteins, to dry the surface and then brown briefly in a ripping-hot sauté pan.
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