Effects of Fermented Shape

[DrJerryrigger]

I've been pondering this recently. I an in need of some more carboys and was thinking about the possibility of making some. I've worked as a glass blower, though its been a wile, and I don't have access to a shop right now.
But I came to the thought; what shape would I make it in.

The basic carboy dimensions (with out getting into calculus) give roughly the least glass used for the given volume, given a flat bottom and domed top. Make scents for making a storage bottle, but may not be ideal for fermentation.

Most of you likely are familiar with the "steam lager" fermenter design, which is a wide shallow vessel.

Then there are the conical fermenters. But I have no idea if there is any advantage to scaling them down.

I was hoping some people had some more information and or thoughts on this topic as it pertains to the home brewer scale.

 

[hopsalot]

if you can made a conical glass fermentor, then you should have never stopped blowing glass for a living

 

[GodsStepBrother]

I know at our small scales the shape of the vessel has little to do with the outcome of the beer. I cannot say that for certain though.

Also Conical’s are a lot more convenient for clearing the beer of yeast and crude on the bottom of the fermentor.

Breweries in Germany brew lagers in wider vessels usually the ratio is 2:1 diameter to height. Apparently in vessels that are taller higher alcohols are produced and more esters are made. Again all of this applies to brewing more than 1,500 barrels at a time. The hypothesized reason for this is increased amino acid utilization caused by the beer circulating via rapid formation of carbon dioxide production. What they mean by that not to certain, but sounds to me like the fermentation is to vigorous and yeasties get stressed out by all the co2 being released into suspension.

If I where you I would go for whatever is more convenient for me as a brewer. There are more important things to worry about than the shape of your fermentation vessel. Think about practicality instead of what it will do to your beer. Unless you’re just very interested in the subject you can make some crazy shaped fermenters.

It would be awesome if you can make something like this, with an airlock or something to vent air out of.

Hope this helped.

 

[johnsonbrad1]

I've recently switched to fermenting in corny kegs since I can fit two of them into a mini fridge I put a love controller in. I was reading that since a corny is so tall and narrow I would see problems with attenuation, due to increased hydro-static pressure. I haven't noticed any problems with my beers finishing any higher than they would have in a carboy. I'm not sure at what point the pressure will start to cause problems, but I'm sure we homebrewers aren't making enough to hit it.

 

[GodsStepBrother]

I ferment in corny's all the time, not problem at all. I do not think it affects so much at our level of brewing.

 

[GNBrews]

I've recently switched to fermenting in corny kegs since I can fit two of them into a mini fridge I put a love controller in. I was reading that since a corny is so tall and narrow I would see problems with attenuation, due to increased hydro-static pressure. I haven't noticed any problems with my beers finishing any higher than they would have in a carboy. I'm not sure at what point the pressure will start to cause problems, but I'm sure we homebrewers aren't making enough to hit it.

On the contrary, many guys have found that fermenting under pressure produces better beers. There's a thread on the forum here: https://www.homebrewtalk.com/f13/closed-system-pressurized-fermentation-technique-44344/

 

[audger]

I was reading that since a corny is so tall and narrow I would see problems with attenuation, due to increased hydro-static pressure

then all those 30 foot tall, 200+ bbl fermentors the big boys use would be having problems as well. there is quite a lot of PSI in the bottom of those tanks. i would suspect any problems that possibly come from using a corney keg would be due to the tall, narrow size somewhat inhibiting the natural convection currents of the beer. if all the yeast hangs out at the top, the stuff at the bottom might stratify somewhat and prolong the fermentation process. or something to that effect anyway.

the conical bottom of the nice fermentors is mainly to help in yeast compaction and reharvesting, and to improve racking the beer off. this is something that isnt as necessary to us little home brewers. i would think that it has only a negligible effect on the actual taste or flavor of the beer- if any difference at all.

On the contrary, many guys have found that fermenting under pressure produces better beers. There's a thread on the forum here: https://www.homebrewtalk.com/f13/closed-system-pressurized-fermentation-technique-44344/

probably due to it reducing the disolved oxygen (DO) content of the beer. closed fermentation and closed transfering = less oxygen contact = better beer. if you can reduce the DO content using any other technique, the outcome should be similar.

 

[GNBrews]

probably due to it reducing the disolved oxygen (DO) content of the beer. closed fermentation and closed transfering = less oxygen contact = better beer. if you can reduce the DO content using any other technique, the outcome should be similar.

The increased dissolved CO2 reduces ester formation. You can effectively ferment a clean beer at elevated temperatures and naturally carbonate at the end. It's a novel technique.

 

[DrJerryrigger]

if you can made a conical glass fermentor, then you should have never stopped blowing glass for a living

Well, I could, but I couldn't put a valve on the bottom, or making it bigger than about 3gal, and it would cost about $300 to make it (plus my time).


I've done some further research on this, and what I keep coming to is that pressure is the biggest factor (as several of you have said). There may be some small advantages and disadvantages to shape, but most are simply convince for the brewer.

I think my next step in brewing will be to get something that I can ferment in under pressure.