Big bottle vs Small bottle carbonation

The last batch of beer I bottled was a little uneven in carbonation, some are perfectly carbonated, some are under. Especially the big bottles. All of them were under carbonated. Does anyone know why this would be?
This is my procedure for bottling. I heat up my sugar water mixture till it just comes to a boil. I then let it rest briefly, and pour it directly into the secondary. I wait about 1/2 an hour to 45min and begin to siphon directly out of the secondary with a bottling wand. I filled the small bottles first and the big bottles last. I left as much air in the bottles as was displaced by the bottling wand.
I'm about to bottle soon, and this time it's very important that the big bottles come out well. So if any one has a good idea why this happened, I love to hear.
thanks
jack

If the priming sugar is mixed thoroughly before bottling you probably didn't let them carb long enough. But if they have been bottle conditioning for at least a month, more than likely though the sugar solution isn't mixed completely before you start bottling so most of the sugar goes into the first bottles and very little into the last ones.

I have had the same problem in the past also and think my problem was one of 2 things:
1. Not thoroughly mixing in the priming sugar enough before bottling
2. Not adding enough sugar.

The remedy to 1. was easy. I prep my priming sugar and pour in 1/2 of the sugar mixture into my bottling bucket. Then I transfer 1/2 of the fermenter into the bottling bucket. Once I have transfered in 1/2 of the fermenter I pour in the remaining priming sugar mixture. This seems like it gave me a more consistet mix.

To remedy 2 check out the following site: The Beer Recipator - Carbonation
Use the site to verify that you are using the appropriate amount of sugar or other priming ingredient.

How long has it been in the bottles? What Temp are you storing them at? What was the OG of the beer....all these factors come into play as to rate of carbonation.

If a few bottles are carbed and some aren't, really isn't about improperly mixed solution...it really mixes itself pretty well...it usually really means the beers not ready yet...each bottle is it's own little microcosm, some even right next to otheres may merely be a tad warmer, and THAT could affect why one beer is done carbing and the other isn't. Waiting another week, and you will more than likely have them ALL carbed...

I have had beers take 8 weeks to carb and condition...It's a natural process...so it has it's own agenda based on the OG of the beer AND the temp of the bottles...It is ACTUALLY theoretically possible to not add any priming sugar and with time to have the beer carb up (for lower grab beer like yours) In fact old english brewing books have recipes that DON'T add sugar...I ran some of the recipes though beersmith, and that corroborated that fact.

You just need more time, that's all I never worry unless it's 8 weeks for a normal grav beer..heck my 1.090 OG Belgian strong took 3 MONTHS to carb....

Read this;
Revvy's Blog, Of Patience and Bottle Conditioning.

Lazy Llama diagramed it best...



Beer under 8 weeks is still WAAAY within my not worry zone...especially if the beer is below 70 degrees.

And yes bottle size does come into play...Larger bottles take longer than smaller ones. I have some pints, 22 oz bombers and other sizes that I often use, but since I enter contests I usually also do a sixer or two of standard 12 ouncers for entering. And inevitably the 12 ouncers are done at least a week faster than the larger bottles....some times two weeks ahead of time...

Big Kahuna once gave a good explanation..

BigKahuna said:

Simple. It's the ratio of contact area just like in a keg. The c02 will need to pressurize the head space (Which takes LESS TIME) in a bigger bottle (More Yeast and sugar, roughly the same head space) but then it has to force that c02 into solution through the same contact area...thus it takes longer.

Click to expand...

You'll find that many people have observed that larger bottles take longer...And comparing 2 at the same time often results in a different taste, becasue they are conditioning at different rates...

https://www.homebrewtalk.com/f14/flavor-differences-bottles-103127/#post1133388

https://www.homebrewtalk.com/f35/bottle-observation-size-matters-101628/

https://www.homebrewtalk.com/f35/does-bottle-size-affect-carbonation-78194/

Hope this helps.

The larger bottle needs more head space than the smaller bottles . You are naturally carbing a larger volume of beer the CO2 goes from the beer to the headspace when the pressure rises the C)2 goes into solution back into the beer. Either leave more headspace or wait longer to drink the larger ones.