Homemade ice

Crystalline ice is when the water from which it comes is free of minerals. The purest ice is formed naturally on the surface of lakes, or when it is produced by special ice makers using filtered water. In the first case, the freezing speed is so low that all impurities present in the water are expelled from the crystal, whereas if we use a freezer, which has a high cooling speed, the ice will be opaque because minerals, gases and bacteria are trapped in the centre of the crystal, which freezes last compared to the sides that adhere to the container being used.

One method of making homemade crystal ice using the domestic freezer is to first heat the water so that the gases present are released, then let it cool and place it, for example, in a heat pack or polystyrene container (foto 3) or in a sea ice cooler, this will encourage very slow freezing. Note that it is necessary to leave the surface of the container open so that the ice crystals form from the top downwards, this is where the ice that will form from the top pushes the impurities out.

You can also opt for a plastic food bag filled with water and placed in a container whose walls have been previously lined with insulating material, such as cardboard (foto 1) or polystyrene (foto 2), this will favour the very slow freezing of the water, the slower the crystallisation, the more crystalline the block of ice will be.

Once ready (foto 4), temper the block by leaving it at room temperature until it is transparent and crystalline, then cut it as you wish using different tools, such as a saw or a hammer and chisel or a punch, a serrated blade knife (foto 5), a mini chainsaw, I use my own technique, a steel wire with handles of insulating material at the ends (to avoid burning my hands) that I heat with a butane torch, in this way the cut will always be clean (foto 6).