Chill filtration is performed by lowering the temperature of the whisky to several degrees below freezing.
At this temperature, the whisky is still liquid, and the chemical compounds have clumped together.
This liquid is then passed through a series of filters, made of materials that range from paper to metal to crushed seashells, that trap all compounds larger than several microns.
The amount of the compounds and sediment removed depends on the number of filters, the speed at which the whisky passes through them, and the pressure at which it’s filtered.