Shapes of Fermenters

[bdbart]

Does anyone know how the shape of the fermenter will affect the brew.

So my logic is this, there are many shapes of beer glasses that will affect head retention, aroma, smoothness....etc..... Why wouldn't there be different shapes of fermenters that create different conditions for the yeast???

I know that there are 'volatiles' in the final beer product, which is the reason behind the different shaped glasses. Some glasses allow the 'volatiles' to be released at slower/faster rates, which affects the taste/smell.

Basically I only know of two shapes of fermenters...conical and carboy shaped. Both designs have a wide area at the top that allow a large surface area for the yeast to get oxygen at the beginning of fermentation. But how would another shape affect that process...i.e. an inverted-conical shape? or maybe an hour-glass shape? or coke-bottle shape?

Does anyone have any knowledge/experience on this subject?

What are your thoughts??

 

[jhoneycutt]

Bumping this

 

[poislb]

Has no effect at all on final product, all co2 is released at the top and yeast settles at the bottom. Temp control is the key, not the shape of the vessel...conicals have certain advantages over a carboy but thats about it...

 

[Flask]

That is a good question. In the book Yeast by Zainasheff and White, a brewery was upgrading to larger conical fermenters. It took them several batches to dial in their fermentation schedule to match the smaller conical's product. I have read this same sort of anecdote in several other sources.

In short, from what I've read fermenter geometry is not well understood.

Fermenter shape on a 5 gal batch might not matter much. But I plan on making an experimental hefeweizen recipe using an open fermenter. If that doesn't get what I'm after, I will be looking into a wider shallower fermenter.

If you end up experimenting, please post it to the forum.

Good luck,

Flask

 

[bdbart]

Has no effect at all on final product, all co2 is released at the top and yeast settles at the bottom. Temp control is the key, not the shape of the vessel...conicals have certain advantages over a carboy but thats about it...

Do you have any sources that have experimented with various shapes?
Or since all research has been devoted to temp., % oxygen, yeast density, sugar content...etc... then that is all people know.

I understand that this is the current thinking, and that conicals offer a more hassle-free setup.

Since most O2 is consumed in the first 48 hours (if not sooner), the shape may not play any role in the process. But does it??

 

[beergolf]

On the homebrew scale the shape is not an issue.

There is a good section in the book Brew Like a Monk that talks about ferementer geometry. It has been a while since I read it but they talked about getting different results from a tall thin fermenter as opposed to a shallower wider fermenter. The reason is that on a big scale the pressure can get pretty high in a taller fermenter.

 

[eastoak]

Has no effect at all on final product, all co2 is released at the top and yeast settles at the bottom. Temp control is the key, not the shape of the vessel...conicals have certain advantages over a carboy but thats about it...

it does have an effect. a shallow and wide open fermentor will give a different flavor profile than a tall narrow fermentor. with really tall fermentors you get pressures on the yeast that can have an effect if not managed. i don't know all of the details about fermentor geometry but i do know it can have an effect.

 

[bdbart]

Thanks for the replies.... I have seen the 'how to brew like a monk' book.....now I have a reason to get it.

 

[wailingguitar]

Convective currents and hydrostatic pressure in tall fermenters tend to produce a cleaner product, shallow vessels tend to produce a more estery beer. One of the reasons that commercial brewers can flip a beer faster is due to tank geometry.

 

[poislb]

based on the speidel tanks we use at the brewery, the blichmann conical we use for test batches and the carboys i use at home there is slight to no difference in the final product. with the speidels we can turn a beer around alot quicker than a carboy but thats really about it. there may be a huge difference when on a much larger scale system but as far as the 200L conicals we use it is very little to none at all.