An ice-water bath chills a can 5–10× faster than freezer air.
Water conducts heat away far better than air — convective transfer is an order of magnitude stronger. Add salt and stir to go faster still.
Only because of contact, not temperature — the ice water is warmer than the freezer. Add salt and it gets faster still. But for something that must not get wet, or a large thermal mass where internal conduction is the bottleneck, the advantage largely disappears.
Estimate with the rule, then check it against the calculator that models it properly.
Open Beverage Cooling Simulator →