Baking a large quantity of potatoes for a crowd presents a unique challenge that goes beyond simply multiplying the cooking time. The goal is to achieve a perfectly fluffy interior and a crisp skin for every single potato, regardless of its position in the oven. While a single medium russet potato typically requires 60 to 90 minutes at 400°F, cooking 20 potatoes simultaneously demands specific adjustments to the method to ensure uniform results.
The Standard Time and Temperature
The ideal temperature for baking a standard russet potato is generally 400°F (200°C), which balances cooking speed with texture development. At this temperature, a medium-sized potato (six to eight ounces) is usually fully cooked within 60 to 75 minutes. This high heat promotes the Maillard reaction on the skin, contributing to crispness.
The heat also transforms the potato’s starches, creating the light and fluffy texture. Russet potatoes are preferred because their high starch and low moisture content allow the starch granules to fully gelatinize and expand. The oven must be fully preheated to the target temperature before placing any potatoes inside to ensure consistent cooking.
Managing a Large Batch
Baking 20 potatoes introduces the variable of oven capacity and airflow, which becomes the primary factor affecting the total cooking time. Heat must circulate freely around each potato to cook it evenly and prevent the skin from becoming soggy. Crowding the racks restricts airflow, causing the potatoes to steam rather than bake, which significantly extends the cooking time.
To manage this volume, utilize two oven racks, typically the middle and upper-middle positions. Ensure a minimum of one to two inches of space between each potato. Placing the potatoes directly on the racks, rather than on a solid baking sheet, further promotes air circulation. Since the oven temperature drops when 20 cold potatoes are introduced, the overall baking time should be extended by 10 to 20 minutes beyond the standard range.
To counteract the uneven heat distribution inherent in a crowded oven, rotation is required halfway through the baking process. After approximately 40 to 45 minutes, swap the potatoes between the upper and lower racks. Additionally, rotate each potato individually to expose all sides to the direct heat, ensuring a uniformly crisp skin and thorough cooking.
Preparation and Testing for Doneness
Proper preparation ensures the best texture and prevents structural issues during the long bake time. Each potato must be thoroughly scrubbed and dried before cooking to remove surface debris. Piercing the skin several times with a fork or knife allows internal steam to escape, preventing pressure buildup that can cause the potato to burst.
For a crisp, flavorful skin, lightly rub the potatoes with olive oil or another fat and season with coarse salt before baking. Confirm doneness by checking the internal temperature, which should register between 205°F and 212°F (96°C to 100°C) using an instant-read thermometer. This temperature range indicates the starches have fully broken down, guaranteeing a light and fluffy texture.