Does A Fermenter Have To Be Cylindrical?

[jivesucka]

Pedobears can hide in sharp corners.

WAT?

 

[Thirsty Boy]

Geometry has a massive impact. for instance, the ratio of hight to width is important, as changes favouring height over width mean for 'bottom yeast', there is a higher concentration of CO2 in solution at the bottom of the fermentor than the top, and this effects the metabolics of the yeast in solution at that particular height. as such, the CO2 concentration can be modeled as a gradient. The CO2 gradient tends to stress yeast more, so if you want more esters, a taller fermentor is likely to throw more esters off, whereas shallow fermentors have a shorter path for the CO2 (well, carbonic acid) to exit the liquid phase, and as such, wide fermentors ferment out more quickly than their taller counterparts (sometimes on the order of days) and usually end up at a lower FG.

Whether you want this or not, is up to you.

Also whether you've got enough reproducibility to actually recieve a significant change (given the extreme variabilities in home breweries) is up to you

On a large scale absolutely - shape and especially depth matters massively. But as Kai said.. on a scale you can fit in your fridge??? I really don't think you are likely to notice the difference between a fermenter with a 30cm wort depth and one with a 45 cm wort depth. If you were talking meters... or even feet that would be a totally different story.