How to Store Walnuts

TL;DR

• Store walnuts below 50°F for short-term storage, with the refrigerator being an ideal spot.
• For long-term storage, keep walnuts in the freezer at 0°F for up to 24 months.
• Maintain a relative humidity between 55-70% for optimal walnut storage.
• Use airtight containers to prevent exposure to air and strong odors.
• Walnuts can stay fresh in the refrigerator for 3-6 months.
• Higher-grade walnuts have fewer defects and more consistent color compared to lower grades.

Introduction

Walnuts are a delicious and nutritious snack enjoyed by many. But to truly savor their rich flavor and reap their health benefits, storing them properly is crucial. Factors like temperature, humidity, and exposure to air and light can all impact the quality of your walnuts over time.

In this guide, we’ll dive into the best practices for walnut storage to keep them fresh, flavorful, and packed with nutrients. Whether you’re a walnut aficionado or just starting to incorporate these tasty morsels into your diet, learn how to make the most of your walnut stash.

Ideal Storage Conditions

Temperature and Humidity

When it comes to walnut storage, temperature and humidity are key. The optimal temperature range is below 50°F, making your refrigerator the perfect spot for short-term storage (1, 2). For longer-term keeping, pop them in the freezer at 0°F (2, 5).

Equally important is maintaining appropriate humidity levels. Too much moisture can lead to mold growth, quickly spoiling your precious walnuts. Aim for a relative humidity between 55% and 70% for best results (3).

Airtight Containers and Odor Absorption

Exposure to air is the enemy of fresh walnuts, causing rancidity and spoilage. Always store your walnuts in airtight containers to keep oxygen at bay. Glass jars or resealable plastic bags work well.

Another consideration is odor absorption. Walnuts are like sponges, easily soaking up strong smells from their surroundings. Store them away from pungent items like onions or garlic to preserve their natural flavor.

Storage Duration and Freshness

Short-term vs. Long-term Storage

The length of time you can store walnuts depends on your chosen method. They’ll stay fresh in the refrigerator for up to 3-6 months (4). The freezer is your best bet for longer storage, keeping them in top form for up to 24 months (2).

Maintaining Freshness

To maintain peak freshness, shell or chop your walnuts only when ready to use them. The same goes for grinding – wait until just before use to prevent rancidity and preserve flavor and nutrition. Whole walnuts will always last longer than processed ones.

Identifying Spoilage

Rancidity and Odor Changes

Even with proper storage, walnuts can still go bad. The telltale sign of rancidity is an off-putting smell and taste resulting from oxidation. If your walnuts give off a paint-like or bitter odor, it’s time to toss them.

Other unusual odors can also indicate spoilage. If your walnuts smell musty, moldy, or just generally unpleasant, err on the side of caution and discard them.

Color and Texture Changes

Visual cues can also alert you to spoiled walnuts. Darkening or discoloration of the nut meat is a red flag. Healthy walnuts should be light brown in color.

Texture changes are another indicator. If your walnuts feel soft, moist, or spongy, they’ve likely begun to mold. Fresh walnuts should be firm and crisp.

Walnut Quality and Shelf Life

Factors Affecting Quality

Not all walnuts are created equal. Factors like harvesting season and sun exposure can impact the quality of your nuts. Walnuts harvested later in the season tend to be darker in color and may have higher tannin levels, leading to a more bitter flavor (6, 7, 8).

The sorting and grading process also plays a role. Higher-grade walnuts (U.S. No. 1) will have fewer defects and a more consistent color and size compared to lower-grade walnuts (U.S. Commercial) (10). Look for top-quality nuts to ensure the best flavor and longest shelf life when shopping.

Maximizing Shelf Life

To get the most mileage out of your walnuts, start by choosing high-quality nuts. Proper storage is also essential – remember those ideal temperature, humidity, and container conditions we discussed earlier.

Finally, consume your walnuts within the recommended timeframe for your chosen storage method. Even with perfect preservation techniques, walnuts won’t last forever.

Conclusion

Proper walnut storage is essential to maintain quality, flavor, and nutritional value. Following the guidelines outlined in this article, you can ensure your walnuts stay fresh and delicious for as long as possible.

Remember to store them at the right temperature and humidity levels, use airtight containers, and avoid strong odors. Monitor for signs of spoilage and consume them within the appropriate timeframe.

With these tips in mind, you’re ready to enjoy walnuts at their very best. Happy snacking!

References

• #1: Walnut – Quality criteria
• #2: Preserving fresh walnuts to maintain nutritional content – MSU Extension
• #3: Optimizing Walnut Storage Conditions: Effects of Relative Humidity, Temperature, and Shelling on Quality after Storage
• #4: Shelled Walnuts: How Long Do Walnuts Last Out of the Shell?
• #5: Storage & Handling of California Walnuts
• #6: Optimizing Walnut Storage Conditions: Effects of Relative Humidity, Temperature, and Shelling on Quality after Storage
• #7: Effects of processing and storage on walnut (Juglans regia L) tannins
• #8: Tannins in Food: Insights into the Molecular Perception of Astringency and Bitter Taste
• #9: Walnut Lumber’s Unique Grading System – Part 1
• #10: Shelled Walnuts Grades and Standards | Agricultural Marketing Service