Mixing of the strike water used for mashing in and milled grist must be done in a way that minimizes clumping and oxygen uptake. This was traditionally done by first adding water to the mash vessel and then introducing the grist from the top of the vessel in a thin stream, but this led to a lot of oxygen absorption and loss of flour dust to the surrounding air. A premasher, which mixes the grist with mash-in temperature water while it's still in the delivery tube, reduces oxygen uptake and prevents dust from being lost.

Mashing in - sometimes