OptionalHigh confidenceStandard, well-understood barware.
Ice mould
A mould used to freeze large-format cubes or spheres of ice for slow-dilution serves.
What it's for: Producing large ice for spirit-forward drinks served over ice.
Don't have one?
Silicone muffin trays or small containers freeze larger-format cubes that work almost as well.
Larger ice has less surface area relative to its volume, so it melts and dilutes a drink more slowly — useful for drinks meant to be sipped over a long time.
Buying guidance
Silicone moulds release ice more easily than rigid plastic ones.