Conical shaped fermenters and why you should never ferment in round fermenters

When Keg King introduced the first PET Conical Fermenter in 2016, we designed it specifically to help brewers achieve peak performance and flavour profiles in their favourite beers.

Over the years, many competitors have tried to copy our products and some have even tried to pass their products as conical shaped even though they are clearly round. As a fun exercise, I asked my 8 year old daughter to draw both a conical and oval shape without explaining to her why and this is what she drew:

cone vs oval

Spelling aside, I think her drawing is pretty clear. So if an 8 year old can tell the difference between a cone and an oval, I’m sure customers can too.

Now let’s talk about why conical shape is important and we will cover this in two simple points: the science behind it and the homebrewing aspect.


The science behind it

In their book “Brewing Science and Practice, 2004” by Dennis E. Briggs, Chris A. Boulton, Peter A. Brookes and Roger Stevens, the authors establish that true conical fermenters a more cost effective, higher fermentability and better ingredients to beer ratio than non true conical fermenters.

True conical fermenters are described as having a steep angle of 70 degree at the bottom which is required to achieve best results

“An important characteristic of these vessels is the steep angled cone at the base. An angle of minimum 70 degrees is required to allow the yeast to settle into the base of the vessel at the completion of primary fermentation. This allows most of the yeast to be separated, leaving the beer comparatively free of yeast. This has allowed, in some systems, maturation and conditioning to take place in the same vessel as fermentation without the need to centrifuge the beer during transfer to a second vessel for maturation”

A number of advantages have been claimed for cylindroconical vessels compared to round fermenters (Hoggan, 1977):

  • lower capital costs of 25-35%
  • lower operating costs of 50-65%
  • decreased beer losses
  • increased vessel utilization
  • reduced losses of bitter substances
  • lower space requirement
  • potential for the collection of carbon dioxide.

Round fermenters producing lesser quality beer (remember my daughter’s drawing?)


Non true conical fermenter pretending to be true fermenters (not angled enough to be called a true conical fermenter)

True 70 degree angle conical fermenters such as the Keg King Apollo, Keg King 60L Fermenter and professional Stainless Still Cylindroconical fermentation vessels:

If world renown Northern Brewer retailer recommends true conical fermenters, they can’t be wrong!:

“Minimize Risk of Oxidation and Infection. Oxidation and Infection are a brewer's worst nightmare. You wait for weeks, only to taste your final beer and find it riddled with off-flavours. Every time you transfer your brew, you remove it from the sealed-off safety of its home vessel, thus exposing it to contaminants and oxygen. Even the most vigilant brewers fall into unintended traps.”


The homebrewing aspect

Looking at it from a homebrewing perspective, why would you want to change from your basic pail or inefficient round fermenter? Quite frankly because it has never been as affordable to brew at home on similar vessels as the professionals do. Science has already claimed that true conical fermenters such the Keg King Apollo provide brewers with better fermentation vessels that are more effective and produce better beer. Not only do you save on ingredients and prevent oxidising you beer, but you get to play with the equivalent of professional equipment at home!

As a homebrewer of 10 plus years, I can safely say that there two things we always do; the first one is efficient use of ingredients & money savings and the second one is playing professional brewer. That’s why you should always use a true conical fermenter like the Apollo and never ferment in round or fake conical shaped once.


Keg King PET conical fermenters

Keg King is very proud to have been the first company to introduce PET conical fermenters to the Australian market and very proud to keep delivering Australian Made fermenters.

Please see a sample of our conical fermenters below: