Half filled bottle peculiarity

[Chrispy92]

Ok so I went ahead an capped the last bottle which was only half full. In addition this bottle sucked out a considerable amount of trub. I am well aware of the issues with CO2 production and potential bottle bombs with half filled bottles / oxygenation etc etc. this was purely an experiment bottle to open in a week and see how the beer tastes.

However I looked at it today, less than 24 hours after bottling and it has a full mini krausen and visible active fermentation in the bottom, visible co2 production (I prime bottles with sugar)

So why has this happened? Did the excess trub being sucked in have a whole lot of yeast that have just gone nuts with the extra sugar? Or is it something to do with the extra headspace. Also.... How long do I have before I should crack this experiment before I really risk a bottle bomb?!

 

[Hoppy2bmerry]

You prime bottles with sugar... Did you put half the amount in this bottle? The yeast that we cannot see that is in suspension is enough to carb, the trub doesn't change that, but if there is extra sugar you'll have extra carbonation. I mix my priming sugar in the bottling bucket if I have a half bottle is has the same amount of sugar as the rest.

 

[Northbank]

What was your gravity when you bottled?

 

[Chrispy92]

Yeah i used less sugar, but probably not quite half the amount.

FG was 1.009 same two readings 4 days apart.

 

[Singletrack]

I am well aware of the issues with CO2 production and potential bottle bombs with half filled bottles...

Why would a half filled bottle be a potential bottle bomb? I think it is more likely to be flat.

 

[Chrispy92]

Why would a half filled bottle be a potential bottle bomb? I think it is more likely to be flat.

From this thread... Some good sciency explanations...

https://www.homebrewtalk.com/showthread.php?t=93202

 

[C-Rider]

I always add priming sugar to the bottling bucket and quite often have 1/2 and or 3/4 full bottles. Never had a bottle bomb.

 

[doug293cz]

Why would a half filled bottle be a potential bottle bomb? I think it is more likely to be flat.

Correct. With approximately equal priming sugar concentrations, the half filled bottle will only generate about 1/2 of the amount of CO2, and internal pressure will also be roughly 1/2, but will vary quite a bit depending on temperature. The pressure in the under-filled bottle will always be less than a completely filled bottle.

From this thread... Some good sciency explanations...

https://www.homebrewtalk.com/showthread.php?t=93202

"Sciency" sounding maybe, but not sound science. The only post in the thread that has correct information is this one. If two bottles have equal internal pressures, then the bottle with more headspace is potentially a more dangerous grenade. But, normal carbonation processes will result in less pressure in the bottle with more headspace, so it is less likely to become a grenade.

If anyone wants to see all the physical chemistry, gas equilibrium math just ask. I can do that to you (and the rest of the innocent bystanders.)

Brew on

 

[Singletrack]

From this thread... Some good sciency explanations...



https://www.homebrewtalk.com/showthread.php?t=93202

Thanks, but the science in that thread is unconvincing. I agree that a half full bottle that explodes is more dangerous than a full bottle that explodes, but I'm doubtful that the half full bottle is more likely to explode in the first place. There's less beer with sugar, so there's less CO2 production and less pressure. There's also more head space for CO2 to compress, so even less pressure. The half full bottle results in flat beer.