Oberon,

The lowest freezing temperature (of a little lower than -20 C / -4 F)
for a brine (NaCl) solution occurs with a brine concentration of about
23% (w/w). So you could aim for that. Disgorgement is often, however,
conducted in brine solutions at -15 C (5 F), which corresponds to a
brine concentration of both 17 and 25%.

Based on that, I'd recommend staying within the range 15-25% brine
solution. A solution of 20% would be ideal. This would require 200 g/l
salt or 1.7 lbs/US gal. Using 1.5 lbs salt per US gal. would be fine.

HTH,
Ben


> What I haven't been able to find in any reference is any mention of the
> ventured into a discussion of salt/water ratios. Not being a chemist, I
> have only the layman's knowledge that water with sufficient dissolved solids
> will remain liquid at a temperature below the freezing point. And I must
> assume that the ice I'll be purchasing at the local convenience store will
> be a decent amount cooler than, say, 30f, so that it'll be able to bring my
> brine solution enough below freezing to do it's trick and freeze the
> champaign in the necks of my bottles. But it would give me a great deal of
> piece of mind to be able to find someone, somewhere, who could say "I've
> used a brine solution of 4 lbs salt in 4 gallons of water. Added 10 lbs of
> ice, and it worked great!"