Beer Pressure difference

[terrym]

I took much more time in preparing the PB and Cap this time, removing the cap seal, soaking in boiling water, cable tieing the injection band etc. Hopefully the extra TLC has paid off.

Why would you need to cable tie the bands? I wouldn't have expected them to move once in position. I certainly would be interfering with things like that.
If its the internal band that's tied which allows gas in, I assume the tie will not stop gas flow in, and if its the external band you have tied hopefully it will not stop it working as a pressure relief i.e. gas can escape at the correct pressure to protect the PB.

 

[OlsBean]

Why would you need to cable tie the bands? I wouldn't have expected them to move once in position. I certainly would be interfering with things like that.
If its the internal band that's tied which allows gas in, I assume the tie will not stop gas flow in, and if its the external band you have tied hopefully it will not stop it working as a pressure relief i.e. gas can escape at the correct pressure to protect the PB.

You tie it below the hole (just above the nipple) to stop it accidental being blown/pushed off the nipple when you inject CO2, which apparently if you believe it, can be a common thing, especially as the band ages and wears. I know they can be replaced, but even though my band was new, it was off, which lead me to a couple of articles and video's about using a small cable tie, which is what I did. Seems to work so far :whistle:

 

[APINTA]

I am back again to tell you I have tested my PB and there is no leaks. But want to ask you experts about the CO2 bulbs when I made this brew I forgot to add the priming sugar so did not have the first load of pressure but instead added a gas bulb which was was fine and gave a pressure of 6 PSI. So when I went to pour my self a beer the pressure went down a bit i had 4 pints last night and the pressure has gone now down to under 3 PSI from 6 PSI so if there is no leaks why did the pressure gone down quite a bit is it because I had no prime sugar at the start when I added the beer to the PB at the start do I have to keep adding more than 1 C02 gas bulb or what. I presume that if I had primed my beer from the start it release its gas slowly or makes a lot more Gas than one Co2 Bulb so is it case of putting 2 bulbs in to the PB

 

[terrym]

When you removed 4 pints of beer from your PB you increased the gas space by the equivalent amount. Since there is no replacement gas immediately available to maintain the pressure, the gas pressure will fall temporarily. However if you leave the PB alone CO2 will slowly leave the liquid beer to re-establish the equilibrium between dissolved CO2 and gas space CO2 and the gas pressure will slowly rise again, until equilibrium is re-established. However the pressure will not be as high as it was before. And the use of priming sugar vs. gas bulbs has no bearing on this process whatsoever.
This then continues, with the internal pressure slowly falling as you remove beer, until the equilibrium pressure in the PB is at atmospheric pressure and at that point you cannot remove any more beer without air glugging back through the tap to balance the internal PB pressure with the outside pressure. Under normal circumstances you avoid air glugging by adding some more CO2 from a bulb, cylinder or more priming sugar, so that the internal pressure is kept above outside pressure.
Finally I re-iterate what I said earlier that you should ignore your PB pressure gauge since it is causing you unnecessary confusion. You don't need it, because if there is enough pressure in your PB to draw off beer fine, and when there isn't you just recharge with CO2. And if it completely loses pressure quickly or never pressurises in the first place you know you have a leak and so you fix it. Simple.

 

[APINTA]

Well Terry in I did what you said took no notice of the gauge and in under a day after drinking a few beers with a friend the Gas went to Zero in a mater of a few hours and could not get any more beer from the Tap This cant be right can it ? I had to put a other bulb OK looked at the gauge this morning it was the same as last night 2.5 no loss of pressure but no increase in pressure either surely when pouring beer you should not lose it that quick and the the pressure should increased with in 24 hours. Ps there is 32 pints still in PB

 

[terrym]

OK.
When you use priming sugar approximately half of the weight turns into CO2 and the rest additional alcohol. So if you prime with 90g table sugar this will generate about 45g CO2. To get the same level of carbonation into your beer at the outset you will need about six 8g bulbs. If you don't put that in initially you will need to top up earlier. And if the beer is colder than 18-20*C this will require more bulbs since the beer has increasing capacity to absorb CO2, and so, relatively speaking, more injected CO2 will find its way into the beer rather than staying in the gas space. Most users of PBs will notice this in the colder weather if they keep their beer in an unheated place, I certainly do. In summer I can get to the bottom of a PB without extra CO2, in winter I can't.
Anyway I think I have now exhausted my repertoire of explanations, so if you need any further advice others will have to help.
Finally I did suggest to you some time back that due to all the problems you get with using PBs you might be better served by just using bottles. They are not as convenient to use, but they are certainly more predictable.

 

[Drunkula]

Great info by terrym. And an 8g bulb of co2 even at room temperature and atmospheric pressure only takes up 4 and a bit litres of space. You can see how you'd burn straight through that if you and your mate had 8 pints between you.

 

[terrym]

Great info by terrym. And an 8g bulb of co2 even at room temperature and atmospheric pressure only takes up 4 and a bit litres of space. You can see how you'd burn straight through that if you and your mate had 8 pints between you.

So raise your glass to Avogadro!

 

[APINTA]

Right I must remember to ADD Priming SUGAR Save a lot of hassle!!! Thank you one again Terry for being so patient with a ***** like me I just did not know how many Bulbs I would need to put it in now I know now sorted Plus the sugar is a lot cheaper as well Again Terry a Big Thank You I will now leave you in peace :thumb: