That's the only thing you need to know about this dish.
Sour cream does the heavy lifting here, acting as both fat medium and moisture binder for the starch. Two full sixteen-ounce containers create a dense emulsion that prevents the shredded potatoes from drying out at high heat. Without that massive dairy volume, the dish breaks down into grease and scorched flakes.
Scaling the Pan Safely
Doubling this mixture requires abandoning the standard 9x13 glass dish. Glass insulates aggressively and traps internal steam, turning the center into mush before the edges brown. Switch to two metal baking pans if you increase volume. Metal conducts thermal energy evenly, allowing the 400 degree Fahrenheit heat to reach the core without scorching the top layer of cheddar.
Chemistry of the Blend
Ranch seasoning contains dehydrated aromatics and salt that draw free water out of the thawing potatoes through osmosis. Mix the dairy and seasoning thoroughly before adding the hash browns. This step ensures the sodium distributes evenly rather than forming pockets of over-seasoned paste. Bake until the internal temperature reaches 165 degrees Fahrenheit and the edges show deep golden browning.