Conical Fermenters Explained: How the Cone Works, Types, and How to Use One

A conical fermenter is a fermenter with a cone for a bottom and a valve at the point of the cone. That one change in shape is why breweries stopped using flat-bottomed tanks fifty years ago, and why it is the first serious upgrade most homebrewers make. Everything that sinks during fermentation, yeast, trub, hop debris, cold-break protein, collects in the cone, and the valve lets you drop it out without opening the tank or moving the beer.

This guide covers what the cone actually gives you, the four kinds of conical you can buy, a dump schedule that works, and how to choose one.

What the cone does

1. You dump the trub instead of racking off it

In a bucket, the only way to separate beer from sediment is to siphon the beer to another vessel. That is a transfer, and every transfer is an oxygen exposure and a contamination risk. In a conical you open the bottom valve for a second or two, the sediment leaves, and the beer stays where it is. "Secondary fermentation" as a step disappears.

2. You harvest clean yeast

Dump the trub in the first day, and what collects in the cone after that is mostly yeast. Open the valve into a sanitized jar at the end of fermentation and you have a pitch for the next batch, free, and cleaner than anything you could scrape off the bottom of a bucket.

3. Long conditioning without off-flavours

Beer sitting on dead yeast for weeks picks up autolysis flavours, meaty and soapy. With the yeast dumped, you can leave a beer in the tank for a month while you wait for keg space.

4. Clear beer at packaging

Cold crash, dump once more, then draw off the racking arm above the remaining sediment. What goes to the keg is bright.

The four types

Type	Cost	Pressure	Temperature control	Best for
Plastic conical	$	None, or 1 to 2 psi	Heat belt or a room	Trying the cone on a budget; scratches over time
Stainless conical, single wall	$$	Often 15 psi	A fridge, or a cooling coil	Ales in a cool basement
Jacketed conical	$$$	Varies	Water or glycol through a jacket	Lagers, cold crashing on command
Unitank (jacketed, pressure-rated)	$$$	15 to 30 psi working	Water or glycol through a jacket	Pressure fermentation, carbonating in the tank, closed transfers

The names get used loosely. Every unitank is a jacketed conical; not every jacketed conical is rated for pressure. If closed transfers and in-tank carbonation matter to you, check the working pressure, not the marketing. Ours is 30 psi working with a 15 psi relief valve fitted.

Jacketed, insulated or a neoprene jacket?

A jacket is a second wall that coolant runs through: it moves heat. Insulation slows heat moving in or out but cannot cool anything. A neoprene wrap on a jacketed tank does almost nothing except trap condensation; we wrote up why.

How to use a conical: the dump schedule

1. 12 to 24 hours after pitching: open the cone valve for one to two seconds into a bucket. Cold break, hop debris and the heaviest trub come out. Close it before you see beer.
2. End of fermentation, before the crash: dump again. This is mostly yeast now. If you want to harvest, this is the dump to keep: sanitized jar, lid loose, fridge.
3. After the cold crash: one more dump for the yeast and haze that dropped in the cold. Then rotate the racking arm upward until the sample runs clear, and transfer.

Two habits that save beer: always have a hose or bucket on the valve before you open it, and open it briefly. A cone dumps fast. And take gravity readings from a sample valve, not by opening the lid.

Cleaning

A conical cleans in place. Rinse, then recirculate hot PBW or a similar alkaline cleaner through a spray ball in the lid for twenty minutes, drain, rinse, sanitize the same way. The parts that come off, valves, gaskets, racking arm, sample valve, soak in the same solution. Because every port is a standard 1.5" or 2" tri-clamp, nothing needs a brush and nothing is a mystery.

Common questions

Conical vs flat-bottom: is it really that different?

Yes. A flat bottom collects sediment as a wide, shallow layer that mixes back into the beer every time you move the tank, and it cannot be dumped without draining the beer. The cone concentrates the same sediment into a small volume at the valve.

Can I bottle from a conical?

Yes. Fit a bottling wand to the racking port, or use a closed transfer kit to a keg and bottle from the keg with a counter-pressure filler. Bottle-conditioning still works after a crash; there is enough yeast in suspension.

What size?

Batch size plus 20 to 25% for kräusen. A 5-gallon batch wants a 6.5 to 8 gallon tank, 10 gallons wants 13. Our Unitank comes in 8, 13, 26 and 40 gallons for exactly that reason, plus a 1 BBL for pilot brewing.

Do I need cooling?

For ales in a room that stays under 68°F, no. For lagers, cold crashing, or any garage in summer, yes. A jacketed tank runs on tap water for ales and takes a glycol chiller for the rest; sizing one is here.

Choosing

• Buy stainless. Plastic conicals scratch, hold flavours and cannot take pressure. They are a way to try the cone, not a destination.
• Check the ports. Standard tri-clamp on the lid, the side and the cone means every accessory from every supplier fits for the life of the tank.
• Check the working pressure. If it is not stated, assume zero.
• Price the whole thing. Lid, valves, thermowell, racking arm and sample valve are sometimes extras.

For the full argument on whether a pressure-rated jacketed conical is worth the money for your brewing, read the honest pros and cons of a unitank. Or tell us what you brew and we will say which tank, or whether a bucket is still fine.