Using Spunding Valve/Force Carb beer questions

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EOWeiss

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Hey everyone, not sure this is the best place to ask this question but, do you cold crash a beer before using a spunding valve? Intuitively if I'm trying to capture some of the CO2 to start natural carbonation, I would think no. But then once I do start force carb with CO2, if I cold crash, there is already more CO2 dissolved in beer than what the chart would suggest? AKA maybe I'd start with 1.5 volumes of CO2 in beer, then cold crash, what would my volume then be? How would I determine how many pounds of pressure from CO2 tank to put on? Any help would be wonderful!
 
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This should help.
 

balrog

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Spunding is typically done when still fermenting, otherwise there's no fermentation gas to spund, build pressure and carbonate the beer. Cold crashing will not add CO2 unless the system is under pressure, with CO2. If that is the case, then the chart we all love, given by @GilSwillBasementBrews will help you find, if YOU KNOW PRESSURE OF CO2 AND TEMP, what the volumes of CO2 dissolved in the beer will be ONCE IT COMES TO EQUILIBRIUM -- my point being that it takes days for CO2 to dissolve unless you're shaking or using carb stone.
 
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EOWeiss

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Thanks guys for immediate response, not sure I asked my question correctly in the first place. So maybe a better question is this, how does this process work step by step lol? Here what I've done:
I've attached my spunding valve as I am at the end of fermentation (within the .004). How long do I allow the beer to sit with spunding valve, if I wanted to naturally carbonate with the valve. OR, how long to let beer sit with spunding if I want to carb beer through my carb stone after that? I've never used a spunding valve and I'm trying to use it to capture some natural CO2 so I don't have to use all CO2 to force carb.
What I'm confused about in using the chart is, if I let the beer sit with the spunding valve (its set to .8 bar and the beer is at 63 degrees) how do I know, without having a Zahm or other tool to measure, how much CO2 will be dissolved in beer before I carb with carb stone? And then if I crash beer to the 30s after having this spending valve on for some uncertain amt of time, wouldn't I set my CO2 regulator to a different amount than what the chart says?
Am I overthinking this?
 
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You’re overthinking it. Just set it to the pressure you want for a given temp. Regardless how much residual co2 is present it will only carb to the pressure you set. Yes you will need less pressure at colder temps than warm to achieve the same volume of co2 in the beer. Again temperature dependent. So if carbing in a fridge go by the chart at the temp of the fridge and volume of co2 desired and set at the according PSI.
 
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