20BBL Conical Unitank Fermenter

A 20BBL unitank is typically the workhorse of a mid-sized craft brewery—roughly 620 gallons of working volume, which usually pairs with a 20BBL brewhouse and gives you enough headspace for high-krausen ales. We build these tanks as true unitanks: one vessel handles fermentation, diacetyl rest, and carbonation, so you avoid transferring between tanks and the oxygen pickup that comes with it.

Materials and fabrication

We default to 304 stainless steel for the body, with 316L available for the cone and any wetted parts if you run sours or high-chloride water. The shell is 3mm, the cone 4mm—thicker than many imports because the cone takes the most stress during CIP and racking. Welds are full-penetration TIG, ground flush on the interior and passivated. Interior finish is 2B mill on the shell and a 320-grit polish on the cone; if you need a mirror finish for yeast harvesting, we can go finer. All wetted seams are pickled and passivated after fabrication. The manway gasket is EPDM as standard, with silicone or Viton on request.

Cooling and pressure

The dimpled cooling jacket covers the cone and lower cylinder, and we can add an upper jacket if you plan to crash cool quickly in summer. Glycol enters through 1.5-inch tri-clamp ports. Working pressure is 15 psi, with a 30 psi test and an ASME-rated pressure relief valve set at 15 psi. That relief valve is not optional—unitanks carbonate under pressure, and a stuck valve or a blocked blow-off can turn a tank into a hazard. We test every vessel hydrostatically before it leaves the shop.

Practical details

The 60-degree cone drains yeast cleanly without a standpipe, and the 20BBL size is the point where many brewers switch from manual to motorized racking arms. CIP is handled through a rotating spray ball in the dome, fed by a 1.5-inch port; returns come off the cone bottom. You will need a dedicated CIP pump and a caustic cycle, not just a rinse. For connections, we typically fit a dry-hop port, a sample valve, a carbonation stone port, and a racking arm—but we build to your piping layout, so tell us what your cellar looks like.

Who this tank suits

Small brewpubs often skip unitanks and use open fermenters, but once you are packaging 20BBL batches and want consistent carbonation, a unitank pays for itself in labor. Commercial breweries running lagers may prefer separate bright tanks, but for ales and hybrid styles, a 20BBL unitank is a common single-vessel solution. If you are scaling from 10BBL, check your floor load and ceiling height first—20BBL tanks are tall, and a 60-degree cone adds height.

FAQ

Can I carbonate in this tank? Yes, up to 15 psi working pressure. For higher carbonation, consider a true bright tank rated for 30 psi.

Why 304 instead of 316L? 304 handles beer and standard CIP chemicals fine. 316L adds molybdenum for chloride resistance—useful if your water is aggressive or you brew sours.

How do I clean it? Rotating spray ball, 1.5-inch CIP port, caustic at 140–160°F, then acid rinse. Do not rely on a simple bucket pump.

What information do you need for a quote? Batch size, beer style, number of tanks, available floor space, ceiling height, and your glycol supply temperature.

Tell us your batch size, beer type, number of fermentation tanks and available space. We can recommend the tank volume, cooling area and configuration for your brewery.