Barrel Headspace

[gordon]

I'm curious to know what effect leaving some headspace in a barrel when it is initially filled might have. Has anyone looked into this? Are there any advantages, or is this simply not a good idea due to an increase of angel share loss?

Thanks!

[MDH]

Keeping the barrel 75% full is advantageous over 100% full. I suspect the reasons for this are what you mentioned, an increased loss of spirit - which actually would help the spirit mellow - but I'm not certain myself. I know many french brandymakers insist on it.