Cook bacon strips in your soup pot over medium high heat until browned and fat is rendered. Remove bacon and set aside, leaving fat in soup pot.
Saute garlic, onion and celery in bacon fat until softened.
Add cooking sherry or white wine and stir, scraping up any browned bits from bottom of pot.
Add potatoes, reserved clam juice, bottle of clam juice , water, chicken bouillon, 1/4 tsp tarragon, salt and pepper. Bring to a simmer over medium-high heat.
Make roux: In a small sauce pan, melt butter over medium heat, stir in flour and cook for 2-3 minutes, stirring continuously.
Slowly add roux to pot of chowder, stirring to combine.
Add heavy cream and remaining tarragon. Simmer until thickened.
Serve with freshly steamed clams and crumbled bacon.