Combine the cubed potatoes, diced carrots, diced celery, and minced onion in a large skillet. Pour in the reserved clam juice and add enough water to cover the vegetables. Cook over medium-low heat, stirring occasionally, until the vegetables are tender, approximately 15–20 minutes.

In a separate large, heavy-bottomed saucepan, melt the butter over medium heat. Gradually whisk in the flour until a smooth paste forms. Slowly add the half-and-half cream, whisking continuously, until the mixture thickens and becomes smooth. This process typically takes about 5–7 minutes.

Gently fold the cooked vegetables, along with any remaining juices, into the prepared cream base. Stir thoroughly to combine, ensuring an even distribution of vegetables throughout the chowder.

Add the drained clams to the chowder just before serving. Stir gently to heat the clams through without overcooking, as this may result in a rubbery texture.

Stir in the red wine vinegar, followed by the salt and ground black pepper. Taste and adjust seasoning as necessary to achieve the desired balance of flavors.

Ladle the clam chowder into individual bowls and serve warm. Garnish with fresh herbs or a crack of black pepper, if desired. Pair with crusty bread or oyster crackers for a complete meal.