Help/advice

[Jalapenjoe]

Hi all,
Any advice on what I can do to save my brew, I made an American pale ale and I have bottled using the coopers pet bottles, I have let them sit for 3 weeks at room temp to carbonate tried one last night and I didn’t hear any pop, 3 weeks and no carbonation the beer tasted good and no sign of oxidation or infection, I have a feeling maybe the caps were not fully screwed on, is there anything I can do to save this batch? Sorry for the long post

 

[Jalapenjoe]

Forgot to mention they are 500ml bottles and I used carb drops, 2 per bottle as stated by instructions

 

[Hazelwood Brewery]

You can add half a teaspoon of sugar to each bottle and keep it somewhere warm (about 20C) for another couple of weeks. First though be sure the room the beer is in is at around 20C and not a cold bedroom for example (if it is a cold room, just move the bottles somewhere warmer). Also before you open each bottle give it a squeeze to see how firm it is in case your issue has affected only some of your bottles, possible if this is a case of not screwing on the cap correctly.

 

[smcc]

I would be surprised if all of them had leaks how many have you tested, I am also assuming you havent filtered or anything prior to bottling that would remove yeast needed for bottle conditioning. I personally dont like PET but thats not helping you

I mean you cant decant them back and refill other bottles that would definitely ruin it. you could just tip them upside down try to get yeast in suspension and put them in place with ambient 20 degrees for another week.

 

[Jalapenjoe]

I would be surprised if all of them had leaks how many have you tested, I am also assuming you havent filtered or anything prior to bottling that would remove yeast needed for bottle conditioning. I personally dont like PET but thats not helping you

I mean you cant decant them back and refill other bottles that would definitely ruin it. you could just tip them upside down try to get yeast in suspension and put them in place with ambient 20 degrees for another week.

I actually tried a few bottles and squeezed the rest and they all don’t really feel that firm, only reason I used pet was to do the squeeze test, I didn’t filter so I will try adding a bit sugar and tipping bottle to get the yeast back in suspension as I didn’t filter this batch

 

[Buffers brewery]

When I fill my PET bottles I squeeze them before I cap them to get the beer up to the brim and then cap tight. They should stay sqidged for a day or so if they’re not leaking then recover as the beer carbonates and releases CO2.

 

[Jalapenjoe]

When I fill my PET bottles I squeeze them before I cap them to get the beer up to the brim and then cap tight. They should stay sqidged for a day or so if they’re not leaking then recover as the beer carbonates and releases CO2.

Good tip mate, thanks

 

[DavidDetroit]

If no proven leaks, up a few degrees for a week and then check progress. I wouldn't add more sugar personally.

 

[Gerryjo]

As mentioned by @DavidDetroit don't add anymore sugar as 2 carbonation drops is plenty for up to 750ml,just raise the temperature or put them in a warm cupboard in the kitchen for a few days and check again with the squeeze test.

 

[strange-steve]

When I fill my PET bottles I squeeze them before I cap them to get the beer up to the brim and then cap tight. They should stay sqidged for a day or so if they’re not leaking then recover as the beer carbonates and releases CO2.

I've often wondered about this, in practice how much extra priming sugar is required to account for the lower pressure in a squeezed bottle?

 

[Buffers brewery]

The pressure in the squeezed bottle will be almost atmospheric pressure cos the bottle’s shape is maintained by....atmospheric pressure. As CO2 is released the bottle reverts to it’s original size after, I’d estimate 10-12 cc of CO2 is produced. After that the pressure will increase above atmospheric as more CO2 is produced. In theory

 

[strange-steve]

The pressure in the squeezed bottle will be almost atmospheric pressure cos the bottle’s shape is maintained by....atmospheric pressure. As CO2 is released the bottle reverts to it’s original size after, I’d estimate 10-12 cc of CO2 is produced. After that the pressure will increase above atmospheric as more CO2 is produced. In theory

If you squeeze a bottle then seal it, isn't the internal pressure lower than atmospheric? Isn't that why it sucks air in when opened? In theory it will "use up" some CO2 to return the bottle to its normal shape and fill the headspace, so I suppose my question is, in practice does this have to be accounted for with extra priming sugar or is the difference negligible?

 

[Hazelwood Brewery]

If you squeeze a bottle then seal it, isn't the internal pressure lower than atmospheric? Isn't that why it sucks air in when opened? In theory it will "use up" some CO2 to return the bottle to its normal shape and fill the headspace, so I suppose my question is, in practice does this have to be accounted for with extra priming sugar or is the difference negligible?

I was also interested. I filled a 500ml bottle with 500ml water and measured how much more would have to be put in to fill the head space. Exactly 50ml, 10%.

There is a compressibility question given that this space is not filled with water but at the pressures we’re working at I don’t think this makes any difference.

This might mean you need to add 10%?

 

[Buffers brewery]

If you squeeze a bottle then seal it, isn't the internal pressure lower than atmospheric? Isn't that why it sucks air in when opened? In theory it will "use up" some CO2 to return the bottle to its normal shape and fill the headspace, so I suppose my question is, in practice does this have to be accounted for with extra priming sugar or is the difference negligible?

I think a Xbeeriment is called for here.... After @Hazelwood Brewery contribution I went down the shed and grabbed one of my (empty) PET bottles, and weighed it full of water and with a headspace I get using my filling method. Full=760 grm, with headspace=712 grm. So my estimate was well out (underestimated neck diameter). So about 50 cc of CO2 for the headspace.
Now for the Xbeeriment. Filled bottle with water and fitted priming cap and connected a length of tubing. Squidged bottle and put end of tube into bowl of water. If the pressure in the bottle is less than atmospheric, water will be sucked into the bottle from the bowl. N.B. the water in the tube is from when I squidged the bottle not from the bowl.

No suction. But what happens if you take the top off?

The bottle popped out eventually but I think that was more to do with the weight of the water than air pressure.

 

[Gerryjo]

I think a Xbeeriment is called for here.... After @Hazelwood Brewery contribution I went down the shed and grabbed one of my (empty) PET bottles, and weighed it full of water and with a headspace I get using my filling method. Full=760 grm, with headspace=712 grm. So my estimate was well out (underestimated neck diameter). So about 50 cc of CO2 for the headspace.
Now for the Xbeeriment. Filled bottle with water and fitted priming cap and connected a length of tubing. Squidged bottle and put end of tube into bowl of water. If the pressure in the bottle is less than atmospheric, water will be sucked into the bottle from the bowl. N.B. the water in the tube is from when I squidged the bottle not from the bowl.
View attachment 41923
No suction. But what happens if you take the top off?
View attachment 41924
The bottle popped out eventually but I think that was more to do with the weight of the water than air pressure.

Time to get the Mentos out.....

 

[strange-steve]

I think a Xbeeriment is called for here.... After @Hazelwood Brewery contribution I went down the shed and grabbed one of my (empty) PET bottles, and weighed it full of water and with a headspace I get using my filling method. Full=760 grm, with headspace=712 grm. So my estimate was well out (underestimated neck diameter). So about 50 cc of CO2 for the headspace.
Now for the Xbeeriment. Filled bottle with water and fitted priming cap and connected a length of tubing. Squidged bottle and put end of tube into bowl of water. If the pressure in the bottle is less than atmospheric, water will be sucked into the bottle from the bowl. N.B. the water in the tube is from when I squidged the bottle not from the bowl.
View attachment 41923
No suction. But what happens if you take the top off?
View attachment 41924
The bottle popped out eventually but I think that was more to do with the weight of the water than air pressure.

This is really interesting actually. I suppose the internal pressure won't be lower as long as the bottle retains its squeezed shape, which of course it will. If somehow the bottle bounced back to its natural shape it would then be at a lower pressure, which is what happens when the cap is removed, the plastic is no longer fighting atmospheric pressure and so bounces back, forcing air into the bottle and maintaining equal pressure, right?

So although it's technically not at a lower pressure, as CO2 is generated internally, the pressure won't increase until the bottle has reformed to its proper shape, which means extra CO2 is required to achieve a certain final pressure compared to a non-squeezed bottle.

 

[Buffers brewery]

This is really interesting actually. I suppose the internal pressure won't be lower as long as the bottle retains its squeezed shape, which of course it will. If somehow the bottle bounced back to its natural shape it would then be at a lower pressure, which is what happens when the cap is removed, the plastic is no longer fighting atmospheric pressure and so bounces back, forcing air into the bottle and maintaining equal pressure, right?

So although it's technically not at a lower pressure, as CO2 is generated internally, the pressure won't increase until the bottle has reformed to its proper shape, which means extra CO2 is required to achieve a certain final pressure compared to a non-squeezed bottle.

Agreed

 

[Buffers brewery]

Just read on line...
“ yeast converts 46 percent of sugar to CO2.”
“ one litre of CO2 weighs 1.96 grams.”
According to my maths that means you need (1.96*50)/(1000*0.46) grams of sugar to produce 50 mls (cc) of CO2. That’s 0.21 grams of sugar. Is that right?

 

[strange-steve]

Agreed

OK so if I'm following this correctly then an additional 50ml of CO2 is required:
CO2 density at 1 atm is ~1.8g/l

50 ml of CO2 required to fill headspace

1.8/20 = 0.1g of CO2

2.16g of glucose or fructose gives 1g CO2

2.16/10 = 0.2g sugar

 

[strange-steve]

Just read on line...
“ yeast converts 46 percent of sugar to CO2.”
“ one litre of CO2 weighs 1.96 grams.”
According to my maths that means you need (1.96*50)/(1000*0.46) grams of sugar to produce 50 mls (cc) of CO2. That’s 0.21 grams of sugar. Is that right?

Just saw this after I posted! We both got the same answer so apparently the difference is negligible