Peel and cut the horseradish into medium-large chunks. Soak water for 1 hour.

Grate in a food processor using the grated, small holed blades or cut by hand into grated bits.

Stir in the swerve, lemon juice, water, and salt. Leave in fridge for 3 hours or more to blend flavors fully.  

Add more of any of those three as you see fit based on taste.