Force carbonating.

Discussion in 'General Beer Brewing Discussion' started by woody1959, Oct 8, 2019.

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  1. Oct 16, 2019 #21

    peebee

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    That's right. Even those casting their minds back to school who didn't do Physics exams*, should have been taught that you can't compress a liquid. But the void about it will have a pressure great enough to stop the liquid CO2 boiling (think pressure cooker), which will be fixed at a specific temperature (about 860psi at room temperature).

    (* That includes me! But school is a very long time ago any way. I just didn't like having these "bombs" about the house and have no understanding of them. Mixed gas is completely different; it does not form a liquid at a reasonable temperature/pressure and so is sold as a compressed gas at 2-3000psi).

    ashock1 Guess we won't get questions off you concerning refilling Sodastream cylinders from Pub bottles!



    :D
     
    Last edited: Oct 16, 2019
  2. Oct 16, 2019 #22

    Graz

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    Find a local supplier. My local gas place does a 6.4kg cylinder for £30 with a £30 deposit. Only paid the deposit once, I just turn up with the empty cylinder and it gets swapped for a full one, pay £30, leave happy, no delivery costs involved. I'm sure others on here can get it even cheaper. That said even at £40 for a refill it gets you about the equivalent of 15 sodastream cylinders (~410g CO2).
     
  3. Oct 16, 2019 #23

    woody1959

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    Seems a bit pointless if I get pub gas, might as well run the keg from that rather than piss around refilling sodastream cylinders.
     
  4. Oct 17, 2019 #24

    woody1959

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    It's almost time to keg my latest cider brew .

    Things I have learnt by experiment.

    It takes 7 days and 5 x 16g CO2 bulbs to force carbonate 18.5L of water at a room temp of 21c and a pressure of 20PSI.

    Things still to learn.

    Whilst I am waiting for the finings to do their stuff on the cider I am going to start drawing the fizzy water off a litre at a time over the next couple of days in an experiment to see how many CO2 bulbs I need to maintain the pressure in the corny.

    Why?.. why not? I know the theories but knowing them is one thing, seeing them operation is a whole different beast, I had 20 16g bulbs knocking around from my cycle puncture repair kit so I thought I would give them a go.

    This information is useful to me because right now I don't brew that much, in fact only just finishing my 2nd brew of this year, however I may increase that, I only have 1 corny and when I keg the cider it will be gassed with sodastream bottles not CO2 bulbs but I will be upping my brewing and getting more Corny's.

    Knowing how many CO2 bulbs it takes to force carbonate and maintain carbonation ( ball park figures) means I can get one of those cheapie CO2 injectors, keg up a brew and leave it, saves buying a 2nd expensive regulator and faffing around with pub gas.

    Is this the right way of doing things? will it have the purists shaking their bags of hops in disgust? no idea, but it's my way of doing things and that's good enough for me.
     
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  5. Oct 17, 2019 #25

    Dexter101

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    As someone just toying with the idea of kegs, that information is really useful so thanks @woody1959

    Be interested to see your results on the amount of CO2 bulbs needed to maintain pressure as well.
     
  6. Oct 17, 2019 #26

    phildo79

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    If the posts are tight and the lid is seated correctly, shouldn't the pressure remain constant? Or at the very least, remain practically unchanged?

    It would be interesting to know if it's possible to force carb a corny with just one bulb, using the 15 minute rolling technique. If so, that would save an awful lot of time, money and hassle.
     
  7. Oct 17, 2019 #27

    woody1959

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    I am down to 15L in the corney ( 1L of water weighs 1KG at sea level, that's how you can quickly tell how much is in a corny, weigh it on bathroom scales and subtract the weight of the empty corny and fittings) and the pressure dropped to about 13psi after drawing the last litre off so I have now put the 6th bulb on.

    Now here's where it gets interesting, the water is now about as carbed as I want it to be so I don't need to keep the pressure at 20PSI and I am now only going to replace the bulbs when it's a 5PSI or less, because all I need pressure for now is for filling glasses, 5 psi will keep the already dissolved CO2 in solution.
     
  8. Oct 17, 2019 #28

    woody1959

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    The pressure will drop as the CO2 dissolves into the liquid, also when you are drawing off the liquid, you are also drawing off pressure as well
     
  9. Oct 17, 2019 #29

    foxbat

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    No it won't. CO2 will come out of solution until equilibrium is reached. See Henry's law.
     
  10. Oct 17, 2019 #30

    Graz

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    Nope, the time taken to carbonate is irrelevant it's all about volumes of gas. To reach a certain level of carbonation the liquid needs to absorb a specified volume of CO2, whether that's done in 15 minutes or two weeks it will still be pretty much that same amount of CO2 used (assuming no leaks). With the rolling technique there will be a continuous flow of gas going in which you'll need more than one bulb to maintain up to the point it's carbonated to the level you want.
     
  11. Oct 17, 2019 #31

    woody1959

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    You're correct, it won't, my bad, it's been 43 years since I left school and I forget a lot of this stuff.
     
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  12. Oct 17, 2019 #32

    Dexter101

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    In line with this, i

    So you would need to maintain 20psi but that wouldn't require any more Co2 until liquid is dispensed? Is that correct?
     
  13. Oct 17, 2019 #33

    peebee

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    Oh dear, it's him (me) again!

    1 litre of CO2 weighs about 1.84g. So 16g of CO2 provides almost 9 litres of gas.

    It will depend on how much CO2 is already dissolved (from fermentation) which could be about 0.9 volumes (about 16-17 litres; guessing, 0.9 is what I use for beer) if the cider was fermented under airlock at room temperature and kept under a blanket of CO2 (most likely, or it might go off) at a temperature no warmer than room temperature (a 100% CO2 atmosphere is essential unless you want to add "partial pressure" to the mix). Note: The water (above) won't have this, hence more capsules will be needed.

    So (get out before my brain explodes …) two capsules might only just be enough, three more likely (the space above the cider must be pressurised too). Chilling to serving temperature (14 or 15C?) will help (CO2 dissolves more easily at a given psi when the liquid is chilled).​
     
  14. Oct 17, 2019 #34

    woody1959

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    Ish...

    20psi if that's the level of carbonation you like and the only way to work that out is to play, currently I am now at 15psi to see what carbonation that gives me as I felt 20psi for water was a bit too bubbly
     
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  15. Oct 17, 2019 #35

    phildo79

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    My head hurts...
     
  16. Oct 17, 2019 #36

    Dexter101

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    you need a beer...
     
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  17. Oct 17, 2019 #37

    peebee

    peebee

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    Noooo… Don't give up. I haven't finished the bit explaining … oops …

    head explodes.jpg
     
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