Strip the thyme leaves from stalks and mince finely.
Mince chives.
Add the blackberries, thyme, chive and beet kvass or brine to a food processor, blender, or directly in a wide mouth mason jar (if using an immersion blender).
Blend until smooth.
Drizzle in olive oil slowly, creating an emulsion.
Season to taste with lemon juice and salt.
Transfer to a jar or bottle. Serve immediately.
Store in refrigerator for up to 2 weeks.