Over simmering water melt and blend 3 Tbsp butter into 3-4 Tbsp flour.
Let simmer for 15-20 minutes, whisking occasionally.
Saute 3 strips bacon, finely chopped with 1 rib chopped celery and chopped onions. When onions are translucent add 1-2 cups of diced potatoes and enough water to cover.
Simmer until tender.
To the roux, whisk in 1 cup of COLD milk.
When blended add another 2-3 cups milk.
Simmer briefly and add to potato base.
Simmer and thicken, then add corn.
Finish with a few spoonfuls of sour cream.