Head Space for Bottling

You don't really need a bigger headspace in a bigger bottle. If you want to reduce O2 exposure, go for the smaller headspace. But if you want exactly the same carbonation level (i.e. volumes of CO2 in the beer) as in the regular bottles, then you want a headspace that is proportional to bottle size.

 

I wouldn't worry about the difference that you will get if you just use the bottle filler normally. It's not exactly proportional, but it's pretty close.

Think about how the filler works. You press it against the bottom of the bottle to depress the spring and wait until the beer gets within a few millimeters of the top of the bottle, and then you pull it up slightly to shut the valve. At that point there's practically no air in the bottle, but as you withdraw the bottle filler, its volume is replaced by beer, which lowers the level of the beer in the bottle, and that's your headspace. So the headspace is, to a very close approximation, the volume of the beer displaced by the submerged portion of the bottle filler.

Now think about filling a bigger bottle. They are typically taller than 12 ounce bottles, so more of the bottle filler will be submerged when the bottle is full, displacing more beer. So already, without doing anything differently, you're getting more headspace by virtue of the bottle's geometry.

Of course bottles come in a lot of different shapes and sizes, so it's not exact. But it doesn't have to be. You'll get close enough just using the bottle filler normally.

 

I suppose everybody has their own technique for filling bottles but I chose to add more beer via withdrawing the bottle filler and pointing the tip on the side of the top of the bottle. The net result is a minimized headspace.

But fill the bottles as you prefer.

Cheers!

 

pour 16 oz of water into the bottle and take note of the fill line ...