My Grandma Leaves Big Pots of Soup Cooling on the Stove for 10 Hours. Can It Stay Out That Long Safely?
Soup is one of life’s simplest comforts. It’s warm, hearty, and packed with flavors that remind us of home. Many of us have fond memories of our grandparents making enormous batches, filling the kitchen with savory aromas for the entire household. But sometimes, traditions raise modern-day questions—like the classic scenario: leaving a big pot of soup on the stove to cool for hours.
You might find yourself wondering, “My grandma leaves big pots of soup cooling on the stove for 10 hours. Can it stay out that long safely?” While it’s tempting to trust the instincts of a home cook, especially one with decades of experience, food safety guidelines tell a more nuanced story. This article explores why leaving soup out for 10 hours can be risky, the science behind foodborne bacteria, and safe ways to store and cool homemade soup.
Why Leaving Soup Out for 10 Hours Can Be Risky
At first glance, it might seem harmless. After all, the soup starts off hot, and the kitchen isn’t exactly a cold environment. However, temperature plays a huge role in food safety. According to the United States Department of Agriculture (USDA), perishable foods should not remain in the "danger zone"—between 40°F and 140°F (4°C–60°C)—for more than 2 hours. The danger zone is where bacteria like Salmonella, E. coli, and Listeria can multiply rapidly.
Here’s what happens when a pot of soup is left out for 10 hours:
Rapid bacterial growth: As the soup cools slowly, it passes through the danger zone gradually, giving bacteria plenty of time to multiply.
Toxin production: Some bacteria, like Staphylococcus aureus, can produce toxins that are heat-resistant, meaning even reheating the soup may not make it safe to eat.
Risk factors increase with size: Larger pots cool more slowly than smaller containers, which means they spend more time in the danger zone, increasing the risk of contamination.
Even if your grandmother has been doing this for decades without visible illness, that doesn’t mean it’s safe—sometimes foodborne illness effects are mild and go unreported, or the immune system of younger family members is more resilient. For seniors, young children, or immunocompromised individuals, eating improperly cooled soup can be dangerous.
How Bacteria Grow in Leftover Soup
Understanding why bacteria thrive in soup can help explain the risks:
Moisture: Soup is mostly water, which is an ideal environment for bacterial growth.
Nutrients: Ingredients like meat, vegetables, and starches provide fuel for microbes.
Warm temperature: As the soup cools gradually, bacteria reproduce exponentially during the hours it spends in the danger zone.
For example, Salmonella can double in number every 20 minutes under ideal conditions. After 10 hours in the danger zone, a small contamination can become massive, increasing the risk of foodborne illness.
Safe Practices for Cooling Soup
The USDA and food safety experts recommend several strategies for cooling soup safely:
1. Divide into Smaller Containers
Large pots retain heat for a long time, slowing the cooling process. To accelerate safe cooling:
Transfer the soup into smaller, shallow containers (no more than 2 inches deep).
Leave the lids slightly ajar until the soup reaches room temperature, then cover.
This increases surface area, allowing the soup to cool faster and reducing the time spent in the danger zone.
