When first racking the last wine I started (a cranberry - currant) into a secondary, I was glad to have enough to fill
the carboy to about 3/4 inch above the base of its neck. I've notcied over the last week that the level has dropped to
the base of the neck as the wine bubbles gently away to itself.

I mentioned this to a fellow wine maker who saw his wine rise over time. This is a new one to me since its the first
time I have had enough wine in the secondary to reach up the narrow neck at all, therefore providing a more accurate
sense of the level of the wine.

I thought before discussing it that it was due to the sugar being broken down and gas being released reducing the
overall level in my carboy. But with my friends testimony added into the equation, I now believe the change in apparent
volume must have been down to temperature as my friends wine rose as he added a brew-belt to avoid cold (and on
reflection mine fell as ambient temperatures fell slightly).

I pressume the change in volume is down to the volume of the bubbles in the wine at given points and think that the
bubbles must be bigger in warmer drinks (lowered viscosity of the fluid perhaps).

Can anyone confirm this or set me straight?

Jim