This question involves a bit of background, so please be patient. I understand that the heat absorbed by ice's phase change from solid to liquid is much greater than the amount that results from the difference in temperature of the ice and the ice cream batter. So the primary cooling effect is from melting, not the initial temperature difference. We add salt to the ice because the freezing point of brine is lower than pure water, which "melts" the ice and absorbs heat. OK. So I'm thinking that putting rock salt onto ice cubes is a pretty inefficient way to create brine -- I always finds a lot of salt in the bottom of the bucket when I'm finished. My "solution" is to make a brine solution (1kg of salt to 1 gal. water) and put it in the freezer for two days, which lowers it to about 4F. I pour the brine into the bucket, and then adding ice. This has markedly reduced the freezing time, and this is where my question comes in. How much of this accelerated cooling is simply due to the temperature difference and total surface contact? Am I getting any benefit from melting, since the brine is colder than the ice? Would a higher brine temperature, say perhaps 25F, promote melting and therefore more rapid heat absorption? Any thoughts on how to calculate an optimal brine temperature (based on a known quantity of batter at a known temperature)? Thanks.