Boston Clam Chowder

I only find recipes, I don't make them up. And this was another great one. Can't remember where it came from, but it was in Word doc I had somewhere.

*Serves 6-8*
1 cup chopped onion
1 cup chopped celery
2 cups diced, peeled potatoes (I use Yukon Gold or Red potatoes)
3/4 cup butter
3/4 cup flour
1 quart half-and-half
2 (6.5-oz.) cans minced clams
1 1/2 teaspoons salt
1 1/2 tablespoons red wine vinegar
Pepper to taste

Drain the clams and reserve the liquid. In a large pot, place the vegetables and pour the claim juice over the top. Add enough water to barely cover the vegetables. Simmer over medium heat until the vegetables are almost tender (don’t overcook them in this step!), about 5 minutes. Meanwhile, in a saucepan, melt the butter and add the flour, making a roux with a wire whisk. Constantly stirring, add the half-and-half slowly. Cook and stir until smooth and thickened, without boiling. When slightly thickened, add the roux to the vegetables and add the clams, salt, vinegar and pepper (to taste). Can keep warm (without boiling!) for a up to an hour or serve immediately.