Small vs. 750 ml bottles

[brownni5]

I'm not that dumb. I consider myself a scientist of sorts. I have an advanced degree in biology that allows me to pay the bills (and buy grain). But my God, I do not understand physics!

When I bottle a Saison for instance, I'll use a mixture of small 330/375 ml heavy bottles and 750 ml/champagne bottles just to get through the bottling quicker, and I always batch prime, filling small and larger bottles in no particular order. I haven't noticed a difference in conditioning time, but this larger bottles are always carbed a higher level than the smaller bottles (or so it seems). I don't see how that can be a function of the amount of priming sugar in the bottle since the amount should be proportional to volume in all the bottles. Is there that much more headspace in a big bottle? It doesn't seem so to me.

It's never been a problem, just something I'm curious about.

 

[Dgallo]

I'm not that dumb. I consider myself a scientist of sorts. I have an advanced degree in biology that allows me to pay the bills (and buy grain). But my God, I do not understand physics!

When I bottle a Saison for instance, I'll use a mixture of small 330/375 ml heavy bottles and 750 ml/champagne bottles just to get through the bottling quicker, and I always batch prime, filling small and larger bottles in no particular order. I haven't noticed a difference in conditioning time, but this larger bottles are always carbed a higher level than the smaller bottles (or so it seems). I don't see how that can be a function of the amount of priming sugar in the bottle since the amount should be proportional to volume in all the bottles. Is there that much more headspace in a big bottle? It doesn't seem so to me.

It's never been a problem, just something I'm curious about.

It could have something to do with the headspace. If youre leaving the same volume of headspace in both size bottles, let’s say an inch from the cap, the larger bottles have a larger volume of beer pbut the same size headspace as the small, which will create more pressure. That’s the only thing I can think of

 

[Vale71]

Actually there is less headspace in a big bottle and that's what's causing carbonation through priming to be more efficient. To be exact, it's the headspace to beer volume ratio that's smaller, causing a smaller fraction of the developing CO2 to be wasted just for increasing pressure in the headspace instead of staying in the beer.

 

[Dgallo]

Actually there is less headspace in a big bottle and that's what's causing carbonation through priming to be more efficient. To be exact, it's the headspace to beer volume ratio that's smaller, causing a smaller fraction of the developing CO2 to be wasted just for increasing pressure in the headspace instead of staying in the beer.

So you’re agreeing, there is proportionally less headspace in the bigger bottle which is causing a more efficient carb

 

[brownni5]

Makes sense. Well, I suppose I don't understand geometry either.

 

[ten80]

So you’re agreeing, there is proportionally less headspace in the bigger bottle which is causing a more efficient carb

To play the Devil's advocate...

if larger bottles have a proportionally smaller headspace than smaller bottles, it would hold that they have a proportiontely greater volume of liquid to carbonate relative to the priming sugar dose, which is calculated off of the full volume of the bottle (i.e., 750 mL). This effectively means a more dilute priming solution, which should result in lower carbonation. So, I have some more thoughts...

I think in reality that the headspace volume has an effectively negligible on carbonation because beers are carbonated to 2.5-3 volumes (i.e., 2.5x750 mL to 3x750 mL) of CO2 dissolved into the beer. Any difference in ratio of headspace volume to beer volume would be very small compared to the several volumes of CO2 dissolved into the beer, AND you must consider that A LOT of CO2 is "stored" in beer as HCO3- (bicarbonate) and H2CO3-- (carbonic acid) in equilibrium with the pressure in the headspace. So in summary, very little CO2 is stored in the headspace relative to the volume of CO2 (as CO2, HCO3-, and H2CO3--) dissolved in the beer.

I think this comes down to a greater efficiency of carbonation with increasing vessel size, but I can't remember a specific source for this fact tucked away in the back of my memory. I'll ponder some more as I hate to present an unsubstantiated idea.

 

[Vale71]

So you’re agreeing, there is proportionally less headspace in the bigger bottle which is causing a more efficient carb

Totally.

 

[Vale71]

To play the Devil's advocate...

if larger bottles have a proportionally smaller headspace than smaller bottles, it would hold that they have a proportiontely greater volume of liquid to carbonate relative to the priming sugar dose, which is calculated off of the full volume of the bottle (i.e., 750 mL). This effectively means a more dilute priming solution, which should result in lower carbonation.

The quoted nominal capacity is not the full volume of the bottle, the headspace is already taken into consideration.

https://www.carllibri.com/Schablone-zur-Fuellmengenkontrolle-05l-Bierflasche-mit-Kronkorken

 

[Dgallo]

To play the Devil's advocate...

if larger bottles have a proportionally smaller headspace than smaller bottles, it would hold that they have a proportiontely greater volume of liquid to carbonate relative to the priming sugar dose, which is calculated off of the full volume of the bottle (i.e., 750 mL). This effectively means a more dilute priming solution, which should result in lower carbonation.

He said he batch primed, meaning that there is a equivalent ratio of beer to priming solution in the solution regardless of the size of the bottle.