Sorry, but I think I am correct. Just because it doesn't fit with what you do does not make it incorrect
I'm not saying that the way you fill bottles is incorrect or that there is anything wrong with doing it that way at all. If it works for you and the perceived benefits outweigh the costs then that's great. I was just saying that I didn't think some of the benefits you listed were quite accurate.
Sorry if I came off a little confrontational, it's hard for me to gauge when typing.
1. With less headspace, you have to get more gas into solution. For a given pressure, a fixed volume can only contain a certain amount of gas. Assuming 2 bottles are at the same pressure, the one with the smaller headspace will hold more gas in the liquid.
The smaller headspace bottle would only have more gas in solution
because the pressure is higher because there is less headspace for the gaseous CO2 to be compressed in. And since you put more primed beer in it, the total amount of CO2 in the bottle will be higher than a less filled bottle further increasing the pressure and making it more likely to burst (if it was overcarbed for some reason) than the larger headspace bottle.
2. When priming, I don't think the yeast consume any O2.
If there is O2 available, the yeast will scavenge it. I'm not sure how much though which is why I said this was probably a valid benefit.
3. Liquid is incompressible, so when the bottle 'explodes' the liquid does not expand, and provides zero energy to make the glass go flying. The energy behind the explosion is the expansion of the gas in the bottle. Yes there is some in solution, but the majority of it is in the headspace. The bigger the headspace, the bigger any potential explosion.
Right, the actual explosion will come from the compressed gas. But the pressure on the glass is the same throughout the bottle. The gas is pushing on the incompressible liquid and the liquid is transferring that force uniformly throughout the bottle. There isn't more pressure on the glass that's touching the headspace than the glass that's touching the liquid. So the total pressure reaching the explosion threshold is what you have to worry about. And like I stated earlier, with a smaller headspace the gas is more compressed and there is more total CO2 in the bottle leading to a slightly higher pressure, which would push it slightly closer to the threshold for explosion. And since the gas is more compressed the explosion will be more forceful if it occurs. You're right that the smaller headspace bottle would have slightly less glass exposed to the expanding gas though. But the glass that does go flying will be slightly more forceful, so I don't know which is better.
But the difference in the amount of headspace is so small that all of this is pretty much negligible anyway. If the bottle is overcarbed enough, then it's going to explode, and it's going to be bad either way.
And I'll let you argue with Papazian about the inch to inch and half in the Commercial bottle.
People don't seem to have any noticeable issues with using the level left by the wand. I was just pointing out that there are a couple of noted Brewers who say that it is not the 'Perfect' fill level, and I agree with them.
And I was just pointing out that the perfect fill level is going to be different for different people depending on what's important to you. For me, and many others, the benefits of a quicker and smoother bottling process outweigh the costs of a larger headspace (mostly because I don't see much cost), but for you they don't. And both ways work just fine with very little difference between them.