Wash and cut all your veggies. Layer the cabbage, cauliflower, beets, carrots in a large, clean, heat-safe jar.
Combine the hot water, sugar, salt, peppercorns, and bay leaves. Stir until the sugar and salt completely dissolve.
Pour it over the veggies until they’re completely covered. Gently press the veggies down with a clean utensil to release any trapped air. Add more brine as needed, leaving 2 inches of space at the top. Use a fermentation weight to keep everything under the brine.
Add a fermentation lid or airlock that allows gas to escape. Set the jar on a plate to catch any overflow and leave it at a cool room temperature, ideally 68–72°F.
Start checking the fermentation around day 3 or 4. The timing will depend on how warm your kitchen is, so use this as a guide rather than a guaranteed finish time. Once fermented, move the jar to the fridge.