Why you should never wash potatoes before storing them
It might feel counterintuitive, but one of the worst things you can do for your potatoes' longevity is to wash them as soon as you get home. Root vegetables are often covered in a thin layer of soil, which acts as a natural protective barrier against bruising and moisture loss. This seemingly harmless dirt is actually a crucial element for maintaining the tuber's condition during storage.
When you wash potatoes, you add moisture to the surface. Even if you pat them dry, residual water remains in microscopic crevices and around the eyes. This damp environment is a breeding ground for mold, fungus, and bacteria, dramatically shortening the potato's shelf life. Research from the University of Idaho indicates that washed potatoes can show a significantly higher incidence of fungal contamination compared to unwashed specimens under the same conditions.
Furthermore, when one washed potato begins to rot, the moisture and bacteria can easily spread to others in the same container, potentially contaminating the entire batch. Proper storage conditions are all about controlling moisture and airflow, and washing your potatoes at the wrong time compromises both of these factors from the start.
The best way to store unwashed potatoes
To maximize the shelf life of your potatoes, focus on creating an ideal storage environment. Here’s a breakdown of the best practices:
- Keep it cool and dark: The ideal temperature for storing potatoes is between 45–50°F (6–10°C). This is cooler than most kitchens but warmer than a refrigerator, which can cause starches to convert to sugar, resulting in an undesirable sweet taste and discoloration. A cool, dark pantry, basement, or cellar is an excellent choice. Keeping potatoes out of direct sunlight prevents them from turning green and developing solanine, a toxic compound that gives a bitter taste.
- Prioritize ventilation: Potatoes need to breathe to prevent moisture buildup. Never store them in a sealed container or airtight plastic bag. Instead, use a mesh bag, a paper bag, a basket, or a ventilated bin to allow for proper air circulation.
- Separate from other produce: Ethylene gas, released by ripening fruits like apples, bananas, and tomatoes, can cause potatoes to sprout prematurely. To avoid this, store your potatoes in a separate location from these other items. A common mistake is storing potatoes and onions together, which accelerates spoilage for both.
The proper way to wash potatoes before cooking
While you should never wash potatoes for storage, it is absolutely essential to wash them right before you cook them. The Centers for Disease Control and Prevention (CDC) recommends rinsing potatoes under running water before cutting. This is crucial for food safety, as it prevents cross-contamination. Germs and soil from the skin can be transferred to the inside of the potato via your knife or peeler.
Here is a simple, step-by-step process for a thorough wash:
- Soak: Fill a bowl with cool water and submerge the potatoes for 15–30 minutes. This helps to loosen stubborn dirt, especially on thick-skinned varieties like russets. For thin-skinned potatoes, a shorter soak or no soak at all is fine.
- Scrub: Under cool, running water, use a clean vegetable brush to scrub the skins clean. For delicate, thin-skinned potatoes, using your hands is often sufficient.
- Rinse: Give the potatoes a final rinse to wash away any remaining dirt particles.
Should you wash potatoes when you buy them? Comparison table
| Feature | Storing Washed Potatoes | Storing Unwashed Potatoes |
|---|---|---|
| Shelf Life | Significantly shorter, often only days | Extended, lasting for weeks or months |
| Spoilage Risk | High risk of mold, fungus, and bacteria growth | Lower risk, especially in a cool, dark, dry place |
| Moisture Content | Increases moisture, creating a damp environment | Remains dry, preventing microbial growth |
| Nutrient Preservation | No impact, but rotting diminishes quality | Better, as natural barriers remain intact |
| Best Practice | Never do this for long-term storage | Always the recommended approach for extending freshness |
What if you've already washed them?
If you have already washed your potatoes, don't despair. If you plan to cook them within 24 hours, you can proceed without issue. If you need to store them for a day or so, the safest method is to submerge them in cold water in an airtight container and place them in the refrigerator. However, this method should only be used for short-term storage (up to 24 hours), as prolonged soaking can lead to waterlogging. After washing, peeling, and cutting, the submerged potato can be safely refrigerated for up to a day.
For those who prefer to eat the nutritious potato skins, washing is always a must. Rinsing under water is standard, but some sources suggest a vinegar-water soak to help reduce pesticide residue. A common ratio is one part vinegar to three parts water, with a 5 to 10-minute soak followed by scrubbing and rinsing.
For more in-depth information on proper storage techniques for all kinds of produce, a resource like Food52 offers comprehensive tips on maximizing freshness. How to Store Potatoes so They Last for Months.
Conclusion: Store them dirty, cook them clean
To ensure your potatoes last as long as possible and remain safe to eat, the golden rule is simple: store them unwashed, and wash them right before you cook. Storing them dirty in a cool, dark, dry, and well-ventilated space prevents moisture-induced spoilage and bacterial growth. The diligent final wash just before cooking is your best defense against soil-borne contaminants and potential foodborne illnesses, even if you plan on peeling them. By following these straightforward steps, you can enjoy fresh, high-quality potatoes for much longer and minimize food waste in your kitchen.
Practical tips for proper potato handling
- Buy unwashed potatoes for longer shelf life. The dirt serves as a natural protectant during storage.
- Store in a cool, dark, and dry place. A pantry or cellar is ideal, but avoid the refrigerator.
- Use a breathable container. Mesh bags or baskets are best for proper air circulation.
- Keep them away from other produce. Especially onions, apples, and bananas, which release ethylene gas.
- Wash only just before cooking. This prevents moisture from causing premature rot and mold.
- Scrub well. Use a clean vegetable brush and cool, running water to remove all dirt and debris.
- Cut out sprouts and green areas. While small sprouts can be removed, excessive greening indicates higher solanine levels, and the potato should be discarded.
