Sorry, saturation is not the right word to describe it. I was thinking of the ice/water analogy and I mistakenly applied it to my heatsink analogy.

The correct limit to the heatsink analogy would a function of the thermal dissipation of the heatsink (material, surface area, thermal resistance) and the qualities of the surrounding fluid (ambient temp, flow, etc). Honestly, my comparison between the ice/water example and heatsinks is not good. It is only appropriate in reference to the “molecular collisions” concept I mentioned before.

How can air get heat saturated? i followed you thus far but its not like humidity, you can always add more heat

When the temperature of the air and temperature of the object you want to cool reach an equilibrium, no heat gets transfered anymore.

You just need a way to spin the can. Probably works better if you speed it up and slow it down or reverse direction repeatedly.

The main reason spinning a can works is because it induces convection inside and outside of the can, which contributes to more collisions and better distributions of collisions. If the warmest soda is in the middle of the can, the cold molecules near the can walls will reach a temperature similar to the ice bath and thud the rate at which heat is transferred becomes stunted.

For lettuce, you’d have better luck finding a way to pass cold water between the leaves, much like having fins on a heatsink (surface area).

Just use your hand. If the beer is in a bottle, leave it so the neck is sticking out of the ice water and spin it that way (this also works very well for wine.) If it’s a can, stick it in vertically, and spin it for 30 seconds at a time or whatever you can stand.

Even if you aren’t constantly spinning it, it will still get cold much faster than any other method. I’ve worked in bars and restaurants for 15 years, and this is my go to, in case of emergency method for chilling beverages.