Protection for your mash
Mash sieves made from copper are used to prevent the mash burning, scorching and sticking to the boiler. Especially useful for coarse mash which has pieces not completely fermented (e.g. stones and peel) - these do not sink to the bottom of the boiler and burn on there.
The mash sieve is placed on the bottom of the boiler and prevents the coarse ingredients from touching the boiler and therefore burning on to it .