Fermenting Under Pressure

[jrsy85]

Hi Everyone,

I have been happily going along with k&k and Oztops for a few years now. My main consumption items are Ginger beer and my apple, pear and honey cider. I have been so happy with the Oztops results that I decided to make BIG ONES, Here are my 2 kegs I have converted into giant pressure fermenters. I have used 100mm lids from milk tankers and 10-220psi adjustable pressure relief valves.
What I want to know is:

1: Is their any reason I can't use these as a primary pressurised fermenter like OZtops?

2: can I setup a counter-pressure fill with inline 1um filter for a commercial(ish) product.

Any input is greatly appreciated.

Cheers,
Joel

 

[raven19]

Main issues coming to mind are the trub you will have to deal with, and the effect of pressure on the ferment - it could lead to off flavours from damaged yeast cell walls (in high pressure situations - similar to tall commercial fermentors).

Just something I picked up after recent discussions with Chris White from Whitelabs.

 

[pokolbinguy]

Completely off topic but....dude there is alot of beer in that photo. 6 fermenters???

 

[crozdog]

Dunno re using them for the main part of your ferment 'cause of the pressure issue already mentioned, but see no reason you couldn't use em as spunding valves towards the end of primary to naturally carbonate. Not sure how you'd deal with the trub, Run the outlet through a filter before you bottle/keg? might have issues with foaming in the filter if you weren't using a pressurised receiving keg... try it & let us know how it goes :icon_chickcheers:

Can you provide some more details on the adjustable pressure relief valves? Where did you get em? cost? fittings?

beers
Croz

 

[jrsy85]

Thanks for the response,

The Relief valves are swagelok SS-RL3M4-F4-MO, they were given to me by a friend who ordered the wrong model for a large (see:Oil Refinery) company, and had them lying around the workshop. So i'm not sure how much they cost.

http://www.swagelok.com/search/find_produc...art=SS-RL3M4-F4 -These ones with the Manual Override handle

I generally don't get a lot of trub because I only really do K&K but I agree with using them as a natural carb only, I might modify a fridge to fit the two so I can cold crash them and just use a counter-pressure filler as usual, no filter.

The two stainless kegs will replace the three small fermenters (20L x2 30L x1) on the left, the one on the right is 60l so i might use it as a primary then move the beer to the kegs, naturally condition, chill then bottle.

Cheers,
Joel

 

[crozdog]

top score!

thanks for the info

 

[dr K]

To keep it simple:
So long as the pressure in your fermentor is not above what you expect your serving beer in the bottle or keg to be then its fine (ish), just make sure you chill to zero C for a few days before attempting to move/decant.
Do not expect to re-use your yeast, it may be a viable yeast but perhaps not a viable strain, the CO2 will likely cause petite mutants.
Expect a reduction in esters.
Expect a reduction in fusel alcohols.
Be prepared, you are going to stress the yeast so make sure you start with plenty, that's viable, and add nutrient, lack of care will result in under-attenuation.

K

 

[Tanga]

Ah! Is that why oztops are so quick (and use so much yeast for so little booze).

 

[jrsy85]

Ok I have been thinking a lot today, I will use the kegs for natural carbonation only.

So here is my workflow plan in my head:

1. Primary ferment in 60L fermenter
2. Rack to keg and bulk prime
3. Set relief pressure to 28 PSI (2.5 Volumes CO2@ 20 Degrees C)
4. chill and settle
5. bottle

I may need more CO2 to keep the keg pressure constant when bottling but this process should keep CO2 use down a bit.

Cheers,
Joel

 

[jrsy85]

I don't intend on reusing yeast for beer brews (for now I guess) I reuse Oztops yeast 3 times and don't notice a difference between new yeast and one thats been through 2 brews. I generally reuse the yeast from apple or apple and honey batches coz it's a clean settled pellet. I've never had an infection but I work in tissue culture so i'm used to sterile techniques (or atleast sanitary until I get a laminar flow up and running). I'll have a read about pressure stress on the little guys and reconsider my options. Thanks for the experienced insight.

Cheers
Joel