Stainless Unitank Fermenters: The Honest Pros and Cons

A unitank is a conical fermenter that holds pressure. That one property changes what you can do on the cold side more than any other upgrade in homebrewing, and it is also why unitanks cost five to ten times what a bucket does. We build them, so you should read this knowing we are biased. We have also talked plenty of people out of buying one. Here is both sides.

What "unitank" means

All unitanks are conicals; most conicals are not unitanks. A conical has a cone-shaped bottom with a valve at the apex, so yeast and trub collect at the bottom and can be dumped. A unitank adds a pressure rating and the ports to use it: a gas post, a spunding valve, a racking arm, a pressure gauge. Ours are rated to 30 psi working pressure and ship with a 15 psi relief valve, which covers everything below.

The pros

1. Closed transfers, no oxygen

Oxygen after fermentation is the enemy of hoppy beer. It turns a bright IPA into cardboard in a fortnight. With a unitank you push finished beer to the keg with CO2 through a sealed line. The beer never sees air. This alone is why most people who buy one never go back.

2. Ferment under pressure

Seal the tank, set the spunding valve to 10 or 12 psi, and yeast produces fewer esters and fusel alcohols at warmer temperatures. Lager yeast at 62°F under pressure makes a clean lager in ten days instead of five weeks. Ale yeast under pressure gives you a rounder, softer beer. How to use pressure by style is its own post.

3. Natural carbonation in the tank

Close the spunding valve near the end of fermentation and the last few gravity points carbonate the beer for you. Or fit a carbonation stone and force-carbonate in a day. Either way the beer arrives at the keg already carbonated and cold. No two-week wait on the gas.

4. Dump trub, harvest yeast

Open the butterfly valve at the cone for a second and the trub is gone. Do it again after fermentation and you are collecting clean yeast for the next batch. Beer sitting on dead yeast for weeks is a thing of the past, so long conditioning does not risk autolysis.

5. Dry hop without oxygen

A hop port with a valve, or a HopDrop that purges with CO2 before it opens, gets hops into the beer without opening the tank. Hazy IPA brewers care about this more than anything.

6. Temperature control that actually works

A jacketed unitank runs water or glycol through a dimpled jacket bonded to the wall. With a controller and solenoid the tank holds its setpoint to within a degree, and it will crash to 34°F on command. A fridge with a bucket in it does neither.

7. It lasts forever

304 stainless does not scratch, stain, or hold flavours. Every port is a standard tri-clamp, so any part from any brewery supply fits. The tank you buy at 26 gallons is the tank a nano brewery would use as a pilot vessel. Thinking about going pro? Price it out with the brewery startup cost calculator.

The cons

1. Cost

An 8-gallon Unitank starts around $1,900. Add cooling and the accessories you will actually use and you are at $2,500 or more before beer. A plastic bucket is $20. Whether that gap is worth it depends entirely on how much you brew and how much you care about the last 10% of quality.

2. It needs cooling

A jacketed tank is only as good as what you run through the jacket. Tap water works for ales in a cool basement. Lagers and cold crashes need a glycol chiller, which is another $1,400 up. Budget for it from the start. Sizing a glycol chiller walks through the numbers.

3. Size and weight

The 8-gallon tank is 34" tall and 39" to the top port. The 26-gallon is 45" tall and much heavier. It does not go in a fridge and it does not go up stairs full. Measure your space, including the height to lift the lid.

4. Cleaning is different, not harder

There are more parts: valves, gaskets, a racking arm, a sample port. Each one comes apart with a clamp and gets soaked. The tank itself is cleaned in place with a spray ball and a pump. Twenty minutes. The people who complain about cleaning a unitank are usually the ones trying to clean it with a brush.

5. Learning curve

Pressure transfers, spunding, purging lines. It is not hard, but the first two batches take longer while you work out an order of operations. After that it is faster than the bucket ever was.

6. You need CO2

Closed transfers and purging need a gas cylinder and regulator. If you keg you already have one. If you bottle, this is another line item.

Unitank vs the alternatives

	Bucket / carboy	Plastic conical	Kegmenter	Stainless unitank
Pressure rating	None	None, or ~2 psi	15 to 30 psi	30 psi working
Trub dump	No	Yes	No	Yes
Closed transfer	No	Rarely	Yes	Yes
Built-in cooling	No	Sometimes, by coil	No	Jacket
Scratches / holds flavour	Yes	Yes	No	No
Sizes	5 to 7 gal	7 to 14 gal	15 to 60 L	8 to 40 gal, 1 BBL, 3 to 5 BBL
Cost	$	$$	$$	$$$$

A kegmenter gets you pressure and closed transfers at a lower price, with no cone and no jacket. If you brew clean ales and are happy with a fridge, it is a reasonable middle step. If you want to dump yeast, crash on command, or brew lagers properly, it is the unitank.

Who should buy one

• You brew IPAs and care about hop aroma lasting past week two.
• You brew lagers, or want to.
• You keg, and you are tired of the oxygen pickup in transfers.
• You brew 10 gallons or more and want one vessel instead of three.
• You are thinking about going pro and want gear that scales.

Who should not

• You brew four times a year.
• You bottle and have no CO2.
• You have nowhere to put a 40-inch tank.
• The budget for cooling is not there yet. Buy the chiller first, next year buy the tank.

Our Unitank, briefly

The Bräu Supply Unitank comes in 8, 13, 26 and 40 gallons, plus a 1 BBL for pilot brewing. 304 stainless, dimpled body jacket, 60° cone with a butterfly dump valve, side sample port, 1.5" and 2" tri-clamp ports throughout, 30 psi working pressure. Cooling is an add-on so you can start with water and move to glycol later without changing the tank. It is also the fermenter inside every BräuPro system.

Still on the fence? Tell us what you brew and we will tell you honestly whether it is worth it for you.

Thinking about going pro? Read how to start a nanobrewery: licences, space and power, and the equipment a 1 BBL brewery needs.