Steam Condenser for Indoor Brewing: How It Works and How to Set It Up
A steam condenser turns boil steam back into water so you can brew indoors without an exhaust hood. How it works, how to set it up, how it changes your boil-off, and a DIY version from a customer.
In this post
The short answer: a steam condenser mounts on your kettle and sprays a fine stream of cold water into the steam coming off the boil, turning it back into water that runs to a drain. You can boil indoors without an exhaust hood, and without steam fogging windows, dripping off the ceiling or filling the house with the smell of boiling wort. It also cuts your boil-off by about 20 to 30%, so adjust your pre-boil volume once.
How a steam condenser works
- Steam rises out of the kettle through a 1.5" tri-clamp port on the lid or top.
- Inside the condenser, a nozzle mixes cold water into the steam. The steam gives up its heat and condenses.
- The condensate and cooling water run out the discharge tube to a drain or a pail, never back into the kettle.
Because the condensate leaves the kettle, the compounds that boil off with the steam, like the DMS that tastes of cooked corn, leave with it. You still get a proper open boil.
What you need
Our steam condenser comes as a complete kit: the stainless condenser, a small submersible pump, a water connection kit with quick disconnects, and discharge tubing. The pump sits in a 5-gallon pail of cold water, so you don’t need a tap nearby, and at a low flow it uses far less water than running the condenser off the tap.
| Your kettle | How it mounts |
|---|---|
| Unibräu, DrainPro kettles, HERMS | On a 1.5" tri-clamp port on the lid or top of the kettle |
| 10G and 20G DrainPro | Or on the optional domed clamping lid, which centres the condenser and seals the boil |
| BräuPro | On a top port of the Unitank, where the BräuPro boils |
How to set it up
- Clamp the condenser onto the top port with a gasket.
- Put the pump in a pail of cold water and connect it to the condenser inlet.
- Run the discharge tube down to a floor drain or a second pail. Keep it open and falling: never submerge or kink the outlet.
- Once you reach a boil, start the water and turn it up just until the visible steam disappears. More flow doesn’t help.
- Hold a steady rolling boil, not a violent one. On a 5,500 W element, around 25% power is usually enough once it’s boiling, and it keeps foam away from the condenser port.
Adjust your boil-off once
A condensed boil loses about 20 to 30% less volume than an open one, depending on how hard you boil and how much cooling water you run. On your first brew with the condenser, note the pre- and post-boil volumes and reduce your starting water to match. Our Brew Day Planner lets you enter your own boil-off rate under “Fine-tune your system”.
A DIY version from a customer
A customer named Glenn built his own from our counterflow chiller: he clamped it to the kettle’s top port with a tri-clamp extension and ran cold water through it to condense the steam. He called it the “condensate steam killer”. It works on the same principle, and you can watch his setup on YouTube. A purpose-built condenser is simpler to plumb and needs far less water.
Frequently asked questions
Do I need an exhaust hood if I have a steam condenser?
No. The condenser removes the steam, which is the main reason people fit a hood. Good general ventilation is still sensible in a small room.
Does a steam condenser cause DMS?
No. The steam and everything in it leave the kettle and go down the drain. Keep a steady rolling boil, and give Pilsner malt beers a 90-minute boil as usual.
How much water does it use?
Much less than a tap-fed condenser. The pump draws from a 5-gallon pail and the water leaves with the condensate, so run the lowest flow that clears the steam and keep an eye on the pail level.
Will it change my recipe?
Only your volumes. Expect 20 to 30% less boil-off and start with a little less water.
More on electric brewing in our beginner’s guide, and on the boil itself in the physics of boiling and cooling.