Your Cart

How to make Corny Keg Fermenter

Corny keg fermenter are the stainless steel canister. These are also known as Cornelius Keg as they were originally made by Cornelius Inc. They are the favorite fermenter for professional brewers because of the following reasons:

  1. The stainless steel design makes it easy to clean. The oval lid is large enough for the hand to go in for a thorough cleaning.
  2. Unlike a glass carboy it is not fragile.
  3. The thin long design increases the surface area making temperature control very precise. Hence it is the fermenter of choice for lagers. It eliminates the banana notes from wheat beers made in summer.
  4. Corny Keg has a robust compact design making it ideal for your chest freezer or fermentation chamber.
  5. These fermenters are multi-purpose. You can still use your corny kegs for dispensing beers. Having a multi-purpose vessel is always a good choice for a hobby brewer as the needs and proficiency changes dramatically.
  6. Kegs can withstand 120PSI. This makes them ideal for pressure fermenting

Today we are going to talk about how to convert your 5 gallon and 2.5 gallon corny keg into a fermenter for home brew beer, wine, kombucha, cider or mead. This might look like a cumbersome process but we would try making it easy for you.

corny keg fermenter
5 from 1 vote

Corny Keg Fermenter

A step by step guide of converting your SS304 stainless steel corny keg into a home brew fermenter
Prep Time10 minutes
Active Time5 minutes
Total Time15 minutes
Course: home brew
Keyword: corny keg, home brew fermenter, low cost home brew, stainless steel
Yield: 1 fermenter
Cost: 6000


  • corny keg 5 gallon or 2.5 Gallon


  • 1 piece wrench or spanner
  • 1 m food grade pipe
  • 1 piece large container for making a blow off setup


  • The Keg is often confusing. Hence here is the names of some of the terms that we use to describe parts of the keg.
    top view of corny keg
  • First step is to sanitize. It is always a good idea to remove all nuts and bolts. Take apart your equipment so that cleaning those hard to reach places is perfect
    7 in one wrench

Option 1: Attaching airlock/ blow off tube

  • Find the gas post of your corny keg. It is the one where dip tube (the long SS tube is NOT ATTACHED)
    ball lock posts
  • Remove the poppet. Use a spanner to remove the spring in the liquid post of ball lock keg. Without the spring, all the CO2 formed during fermentation will immegiately get eliminated.
    ball lock keg valve height
  • Also remove the small SS dip tube below the gas post.
    If the Krausen touches that, then the CO2 release is blocked. This will also allow you to eliminate dead head space further and increase the capacity of your keg.
    keg poppet and dip tube
  • Now attach the pipe connector (you can get at any hardware store) to the keg post. Connect it with the blow off tube and your fermenter is ready
    tap attachment, keg blow-off fermenter

Option 2: Pressure Fermenter

  • Use a ball lock gas connect. Attach the connect and inset it on the ball lock post
    gas connect for ball lock kegs
  • You can now attach, detach and maintain the desired pressure in your fermenter for pressure fermenting beer. If by any chance the yeast krausen comes all the way to the top, you don't have to worry about oxidation. Simply remove the gas connect, clean/sanitize and reconnect
    attaching connectors to corny keg

Attaching the Siphon

  • There are three ways to attach a siphon.
    1. Take out the large oval lid and use a regular siphon
    2. pressure ferment and use the dip tube to start the flow. The CO2 pressure will force the beer through the dip tube and liquid post to start the flow. However you will have to file/bend the dip tube so that it is above the sediment aka trub level.
    3. Use a carbonation lid. It has a ball connect that will allow you to attach the silicone tube for siphoning.
    create fizzy beer and frothy ciders
  • The beverage ports have a valve. So it can be used to draw out periodic samples for your testing and tasting purposes without any risk of oxidation
    attaching lid to corny keg

Dry Hopping

  • Once the primary fermentation is done, you can use a dry hopping tube to infuse hops, oak chips or spices. This is pretty handy for double IPA style beers and red wine that need a bit of oak.
    tube for hops keg compatible
  • Don't forget to use a food grade rinse free brewing sanitizer to clean the equipment before and after every use.
    brewing sanitizer rinse free


I love kegs because they are inexpensive and indestructible.

Buy Related Products

Make a multi-purpose fermenter, aging & dispensing uni tank out of a stainless steel SS304 Corny keg. Ideal for beer, wine, and pressure fermenting with precision temperature control.
One of the biggest advantages of keg fermenting is that 7-8 of these kegs can fit into a single chest freezer (ice cream refrigerator) making it easy to conduct variety of home brew experiments simultaneously.


Beer Keg home brew fermenter

One comment

  1. 5 stars
    thanks Kishore for sharing

Leave a Reply

Your email address will not be published. Required fields are marked *

Recipe Rating