Ice used to be dirty with soil, sawdust, pollution or poor hygiene.

European ice harvesters would store the ice in in underground pits for insulation. The melting ice water picked up dirt and covered the blocks. Or the blocks were covered in saw dust for insulation.

Americans stored their ice above ground in huts. When the ice water melted it dropped out the base and benefit was creating an evaporative cooling effect.

Both types of harvested ice were good for refrigerators, or cool rooms, making ice cream, but only the American style ice was good for mixed drinks.