Rinse the tomatoes under cool running water and pat them dry completely.

Using a sharp chef's knife, cut out the core from each tomato and quarter them.

Place the quartered tomatoes into a large pot, add 2 cups of water, and stir gently.

Heat the pot over medium-high heat until it reaches a gentle boil, then reduce to medium and simmer for 12 to 15 minutes until the tomatoes collapse into a pulp.

Carefully transfer the cooked tomatoes and liquid to a blender in batches and blend until completely smooth, about 45 seconds per batch, or use an immersion blender directly in the pot.

Strain the blended tomato mixture through a fine-mesh strainer lined with cheesecloth into a large bowl, pressing with the back of a spoon to extract all the juice.

Return the strained juice to the pot, add sea salt, black pepper, lemon juice, garlic powder, and onion powder; stir well and adjust seasoning to taste.

Pour the juice into clean glass jars or bottles, refrigerate for at least 1 hour until chilled, then serve over ice or use as desired.