Spunding valve and Plato to CO2 production

[xico]

Hey all, I am going to pick up some spunding valves for my keg fermenters. What has been people's experience in terms of how to control the fermentation to yield its own CO2 production? I visited a research brewery recently that yields half its CO2 from the yeast. The reason is to preserve volatile aromatics and after tasting what they make the last year I'm convinced it's where I want to go.

Any thoughts on building them over purchase? How much pressure do I need to retain in the unit to keep CO2 in solution while also not overly stressing the yeast? Does 2 psi effectively double the potential volumes?

Thanks in advance!

 

[dryboroughbrewing]

Is there anyone selling homebrew spunding valve setups? I own 4 personally, and I love them.
My older 2 are built like this (except I used a cheaper brass T)
http://www.homebrewfinds.com/2011/02/build-spunding-valve.html

My newer 2 that I just put together the other day are built more like this (got a great deal on the nogren PRVs on ebay):
https://www.homebrewtalk.com/showthread.php?t=317333

I personally ferment at 5ish PSI during the first week or thereabouts, after that I turn it up to 30 PSI to finish the ferment and leave me about dead on serving pressure-wise, day 10 I'm usually crashing the beer (after removing the PRV)

 

[schematix]

I built my own spunds based on a thread around here using McMaster parts. They do the job during primary but they have an ultra slow leak so are ineffective after that. I usually just pull the spund off and spot check the pressure every day or two. So far that's been working. Annoying but it works.

Overall I have been REALLY satisfied with keg fermentation. I've been doing primary at 3.5 psi. It keeps the kraussen WAY down (about 1cm with lagers, more with ales). I fill the keg to the top weld and still have another 1cm i think i could go. I have all my gas dip tubes cut to by flush on the inside.

To set the carbonation pressure just consult your standard co2/temperature/volumes chart. If you're doing an ale at 70F you're gonna need >30 psi, while lagers at 40F are more around 12 psi.

 

[TexasWine]

I just started pressure fermenting in kegs this summer. I've been happy with this one I purchased. My only complaint would be that the gauge should have a smaller range, say 0-30 psig.

http://www.homebrewing.org/Adjustab...FeJh41rQINRqf3vuwkP6a7Vbmd-GNDPuFwaAhMo8P8HAQ

I would purchase instead of build. My experience was that there was little to no cost savings building it yourself. Oh yeah, I built one as well following one of the how to threads on here. I don't use it now that I have this one.

Also, I built a gas manifold so I can connect up to four kegs to this single relief valve.

 

[techbrau]

You need about 1% fermentable extract (or 4 gravity points) to fully carbonate the beer.

If your measurements and timing are good enough, you can rack to a keg when you are 4 gravity points above FG and let it finish up in there without actually needing a spunding valve.

 

[xico]

Thanks everyone, all great information. I am intrigued by the idea of chaining fermenters to one. My lady and I usually make 18-20 gallon batches, 2 or 3 times a month so making most of fewer items is best. We like 4-5 gallon batches so we can experiment with dry hopping, yeast blends, so on.

The DIYer in me wants to make one, and dryboroughbrewing's model is just what I would like to assemble. But I have wholesale access to homebrew supplies and a line on ball lock spunding valves with 0-30psi for ~13 dollars. They are cheap, and I expect a lemon or two but I figured I'd try those out first.

I just found out today that I have two sankes coming my direction I will turn into fermenters. I have had my eye on a fermenter conversion with a thermowell, blowoff, and racking arm on a compression fitting. If I had the folk who make it weld the blow-off portion with a 1/4" MPT threading I could then attach lines to a manifold and/or valve directly, right?

 

[techbrau]

I don't like the idea of connecting spunding kegs together with a manifold. Each time you connect a new keg to the chain you're just introducing a whole bunch of new oxygen to the entire system. I really see no reason to do it other than to use one single spunding valve, but you shouldn't really need to keep a spunding valve attached to a keg for more than a couple days after racking.

 

[MrFancyPlants]

I don't like the idea of connecting spunding kegs together with a manifold. Each time you connect a new keg to the chain you're just introducing a whole bunch of new oxygen to the entire system. I really see no reason to do it other than to use one single spunding valve, but you shouldn't really need to keep a spunding valve attached to a keg for more than a couple days after racking.

Unless you first fill up your kegs with water and then push the water out

 

[TexasWine]

I really see no reason to do it other than to use one single spunding valve,

I've got a great reason. You can't fit an 8 gallon batch in one 5 gallon keg.

 

[techbrau]

I've got a great reason. You can't fit an 8 gallon batch in one 5 gallon keg.

So you have 2 gallons of airspace in one of the two 5 gal kegs? Ouch.

Why not just step up to 10 gallons?

I think it's important to completely fill kegs to the brim when spunding them.

 

[TexasWine]

So you have 2 gallons of airspace in one of the two 5 gal kegs? Ouch.

Why not just step up to 10 gallons?

I think it's important to completely fill kegs to the brim when spunding them.

I'm fermenting in them.

 

[Chirobrewer]

If I were to ferment in a 5 gal corny, and naturally carbonate, would a counter pressure bottle filler work using the natural fermentation CO2 pressure or does that require additional gas? I've never tried any of what you guys have done in this thread, just playing around with ideas.

 

[schematix]

If I were to ferment in a 5 gal corny, and naturally carbonate, would a counter pressure bottle filler work using the natural fermentation CO2 pressure or does that require additional gas? I've never tried any of what you guys have done in this thread, just playing around with ideas.

You'll need additional CO2 to push it.

 

[xico]

I assume you would need to set your filler to the same pressure as the keg? Can someone confirm that? If I am correct, it may be good to cool your corny as low as you can so you can drop the psi needed to move the beer and thus reduce shaking too much gas out of solution.

 

[schematix]

When i bottle from a keg i usually push with less than i'd serve with so i have less foaming. 4-5 psi seems to be a good balance between speed and foaming.

 

[xico]

So I have built several spunding valves with the parts suggested in this thread and have had a lot of trouble getting them to work. The adjustable pressure relief valves (I bought 3) all seem to either release below or way above the set pressure. I have been calibrating them using both my CO2 regulator's gauges (one has been 2 psi low for about a year). When I disconnect them without turning the relief gauge and attach it to the corny things fall apart.

Any thoughts? Did I buy bunk hardware? Anyone have any suggestions? It'd be great to dial this in.

 

[TexasWine]

How exactly are they behaving? Spring operated relief valves do not go fully open until they're above set pressure. When they do go fully open, you'll hear a big pop. The valve will finally reseat at some point below the set pressure.

You might already know all this, but I say it because some folks buy these valves thinking they're defective when they act this way. But it's just the nature of the design.

 

[xico]

So far they don't seem to release at all. My beers become over-carbonated in the process, hefeweizen volumes. They work fine when attached to the CO2 bottle and I adjust the valve. But when attached to the corny I get overcarbed beer every time.

 

[MaCheFai]

I used this pressure relieve valve (along with a gauge) in my build based on a recommendation and it works great. I set it to 15 psi and let her go: https://www.morebeer.com/products/stainless-gas-pressure-relief.html

And I use 15psi based on this: http://scottjanish.com/fermenting-dry-hopping-pressure/
as well as a beersmith podcast that mentioned the best pressure for fruity esters was 15psi.

 

[ajdelange]

I visited a research brewery recently that yields half its CO2 from the yeast. The reason is to preserve volatile aromatics and after tasting what they make the last year I'm convinced it's where I want to go.

[/QUOTE]That's most interesting. I believe that most breweries that recover CO2 scrub it thoroughly to get the "Jungbuket" (i.e. stinky volatiles) out. I certainly rely on CO2 production in the lagering vessel to carry those off for me.