Fermenters and temperature control

Buckets, PET and glass carboys, stainless and pressure fermenters, airlocks and the controllers and heaters that keep yeast in its range.

Plastic fermenters with airlocks beside a small stainless conical fermenter
Photo: paulmed, CC BY-SA 2.0, via Flickr
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Glass carboys breakGlass carboys can break and cut. Use a good carboy handle and always support the bottom when you move a full one; a crate or carrier under the base helps on slippery floors. Never pour hot wort into cold glass. PET and stainless avoid the risk.Source: Craft Beer & Brewing: Homebrew safety

How to choose a fermenter for homebrew

The best fermenter for homebrew is the one you can clean well and carry safely when it is full. A 5-gallon batch needs a vessel of about 6–7.9 gal so the krausen has headspace. Material decides the rest: plastic buckets are light and cheap, PET carboys let you watch the beer, glass resists scratches but breaks, and stainless lasts for decades.

Fermenter materials (examples from the catalogue)

TypeExampleListed volumePressure
HDPE bucketHome Brew Ohio bucket with airlock6.5 gal✗ Not rated
PET carboyFerMonster wide mouth6 gal✗ Not rated
Glass carboyHome Brew Ohio carboy5 or 6.5 gal✗ Not rated
Stainless bucketSs Brewtech Brew Bucket7 gal✗ Not listed
PET pressure fermenterFermZilla All Rounder kit30 L (7.9 gal)✓ 2.5 bar (36.2 psi)

Source: Product listings and KegLand

Pressure ratings: read them before you add CO2

Pressure fermenters let you ferment warmer with less ester, carbonate in the vessel and transfer without oxygen. Every one has a ceiling, and a spunding valve or PRV keeps you under it. Never exceed the rating printed by the maker.

Listed maximum pressure

Maker or listing figures

VEVOR 30L stainlessVEVOR 30L stainless: 15 psi15 psiFermZilla Tri-Conical 27L (2.4 bar)FermZilla Tri-Conical 27L (2.4 bar): 34.8 psi34.8 psiFermZilla All Rounder 30L kit (2.5 bar)FermZilla All Rounder 30L kit (2.5 bar): 36.2 psi36.2 psi
Source: Product listings; 1 bar = 14.5 psi
CO2 cylinders and pressureKeep cylinders upright and secured, and always use a CO2-rated regulator (US CO2 tanks use the CGA 320 valve fitting); never connect a cylinder straight to a keg. Store tanks cool and away from heat. CO2 displaces oxygen and collects low: ventilate, close the tank valve and leave the room if a tank leaks. Never exceed a fermenter’s or keg’s rated pressure.Source: Kegco: Everything you need to know about CO2; OSHA hazard bulletin on CO2

Temperature control for steady fermentation

Fermentation makes its own heat, so beer can run several degrees above the room. A dual-stage controller switches a fridge for cooling and a heat wrap for warming; tape the probe to the fermenter wall under insulation. The Inkbird ITC-308 lists 1100 W maximum at 110V on one listing, so check the manual before you plug in a large load.

Want hot-garage options and kveik? See the summer brewing hub.

Fermenter mistakes to avoid

  • Scrubbing plastic with abrasive pads: scratches hide bacteria. Use a soft cloth and a cleaner.
  • Filling to the brim: leave headspace or use a blow-off tube for active ales.
  • Moving a full glass carboy by its neck: carry it by the base in a crate or carrier.
  • Pressurizing a vessel that isn't rated for it: only pressure fermenters with a PRV or spunding valve.
  • Reading the room thermometer instead of the beer: put the controller probe on the fermenter.

Related reading: KegLand FermZilla review, Inkbird ITC-308 review and best conical fermenters.

Fermenters & temp control: questions

What is the best fermenter for homebrew beginners?
A food-grade plastic bucket of about 6.5 gal with a lid and airlock. It is light, cheap and easy to clean. Move to PET, stainless or a pressure fermenter later if you want clarity, longevity or closed transfers.
Plastic or glass fermenter?
Plastic and PET are light and won't shatter but scratch if you scrub them hard. Glass doesn't scratch but is heavy when full; carry it by the base in a crate, never by a neck handle alone.
How full should a fermenter be?
Leave room for foam. A 5-gallon batch usually goes in a 6–7.9 gal fermenter; use a blow-off tube instead of an airlock for vigorous ales.
Can I ferment under pressure in any fermenter?
No. Only vessels rated for pressure, such as the FermZilla pressure kit (2.5 bar, 36.2 psi per KegLand). Buckets and carboys are not pressure vessels.
Where should the temperature probe go?
Against the side of the fermenter, under a piece of foam or insulation, so it reads the beer rather than the air in the chamber.