What Not to Put in a Dehydrator: A Complete Guide to Avoid Costly Mistakes

Dehydrating food is a time-tested method of food preservation that brings numerous benefits, from extending shelf life to intensifying flavors and creating healthy, portable snacks. With the increasing popularity of home food dehydrators, many people are experimenting with drying everything from fruits and vegetables to meats and herbs. However, not all foods or materials are safe or suitable for dehydration.

Understanding what not to put in a dehydrator is just as crucial as knowing what you can. Placing the wrong items in your machine can result in ruined equipment, compromised food safety, fire hazards, or even health risks. In this comprehensive guide, we’ll dive deep into the foods, substances, and behaviors you should avoid when using a dehydrator, so you can dehydrate safely and successfully.

Why Knowing What to Avoid is So Important

Before listing the unsuitable items, it’s essential to understand why the question matters. Dehydrators work by circulating warm, dry air to gently remove moisture from food. While this process is gentle compared to ovens or microwaves, it operates over extended periods—sometimes up to 48 hours—making it vulnerable to issues if improper items are introduced.

Some key consequences of placing unsuitable items in a dehydrator include:

• Food spoilage or bacterial growth
• Damage to the dehydrator’s heating elements or trays
• Unpleasant odors that linger in the unit
• Fire hazard from high-fat or oil-rich materials
• Wasted time, energy, and ingredients

With proper knowledge and caution, you can avoid these pitfalls and get the most from your dehydrating experience.

Foods That Should Never Go in a Dehydrator

While many foods dehydrate beautifully, others either fail to dry properly, become unsafe, or produce undesirable results. Below, we detail each category of inappropriate items and explain why they don’t belong in a dehydrator.

High-Fat Foods (Dairy, Oily Meats, Avocados)

Fat and oil do not dehydrate well, and when heated over long periods, they can turn rancid and pose safety risks. Foods high in fat should be avoided or used with extreme caution.

Dairy Products

Most dairy items, such as milk, yogurt, cheese, and cream, contain significant moisture and fat. When exposed to prolonged heat, these products:

• Can spoil rapidly due to bacterial growth
• Develop unpleasant textures and odors
• May leave a greasy residue on trays, making cleaning difficult

While powdered milk can be stored long-term, it’s not made by dehydrating liquid milk at home. Attempting to dehydrate milk or cheese at home may lead to spoilage rather than preservation.

Fatty Meats

Although lean meats like beef jerky are popular in dehydrators, fatty cuts of meat are a no-go. The fat in meats such as pork belly, bacon, or heavily marbled beef:

• Melts during dehydration, dripping onto trays and heating elements
• Can become rancid, leading to off-flavors and potential food poisoning
• Increased risk of smoke or fire if fat contacts a heating coil

If you’re making jerky, trim all visible fat from the meat before processing. Lean cuts like eye of round or flank steak are ideal.

Avocados and Other High-Oil Fruits

Avocados are rich in healthy fats, but these fats are unstable over time, especially when dehydrated. Dried avocado:

• Turns brown quickly due to oxidation
• Develops a rancid taste within days
• Can leave an oily film on trays

While avocado powder is commercially available, it’s made using specialized industrial processes and often includes antioxidants like ascorbic acid to stabilize it. Home dehydrators lack these capabilities.

Whole Fruits and Vegetables (Without Pre-Cutting)

While apples, tomatoes, and bananas dehydrate excellently, you should never place them in the dehydrator whole. Uneven drying occurs when moisture can’t escape from the center.

For example:

• A whole apple will dry on the outside while the inside remains moist, leading to mold
• An entire potato won’t dehydrate fully and can harbor dangerous bacteria like Clostridium botulinum

Always slice fruits and vegetables uniformly (about 1/4 to 1/2 inch thick) to ensure consistent drying. Smaller pieces also reduce drying time.

Raw Eggs

Dehydrating raw eggs at home is unsafe and inadvisable. Eggs carry a risk of Salmonella, and the low heat of a home dehydrator (typically 95°F–160°F) may not kill harmful bacteria effectively. Unlike high-temperature pasteurization used in commercial egg powder production, home units do not reach consistent, sterilizing temperatures.

Additionally, eggs contain moisture and protein that, when dried slowly, can create a breeding ground for pathogens if not handled correctly. If you want powdered eggs, it’s better to purchase commercially dehydrated versions that are pasteurized and tested for safety.

Butter and Oils

Never place butter, coconut oil, olive oil, or other pure fats in a dehydrator. These substances will liquefy during the heating process and either drip through the trays or coat the interior. The result is:

• Difficult to clean residue
• Potential damage to the machine’s components
• Fire hazard if oil contacts electrical or heating parts

If you’re adding oil to foods (like seasoning vegetables), do so lightly and avoid soaking the food in oil before dehydration.

Non-Food Items: What Else Belongs Outside the Dehydrator

Dehydrators are designed exclusively for food. Placing non-food items inside, even with good intentions, can lead to hazardous outcomes.

Flowers for Potpourri (Without Caution)

While drying flowers in a dehydrator is possible, it’s not always safe or recommended. Some flowers contain essential oils that could:

• Damage plastic trays or seals over time
• Leave strong residual scents that taint future food batches
• Pose a risk if used for both food and ornamental drying without strict separation

If you must dry flowers, use parchment-lined trays and dedicate a separate dehydrator for non-food use to prevent cross-contamination.

Herbs Treated with Chemicals

While fresh herbs like basil, thyme, and mint are excellent for dehydration, herbs sprayed with pesticides or fertilizers should never be dried. Chemical residues can concentrate during dehydration and lead to health risks when consumed.

Always use organic or thoroughly washed herbs. If you’re uncertain about the safety of the source, skip dehydration.

Wet Cloths, Laundry, or Shoes

Contrary to some internet DIY hacks, dehydrators are not substitutes for dryers. Attempting to dry wet clothes, shoes, or towels can:

• Overload the machine, causing motor strain or burnout
• Trap moisture inside components, leading to mold or corrosion
• Introduce dirt, lint, or bacteria into the unit

These non-food uses can void your warranty and create long-term hygiene issues. For drying fabrics or gear, use a clothes dryer or air-dry instead.

Preparation Mistakes: What You Shouldn’t Do Before Dehydrating

Sometimes, it’s not the food itself, but how you prepare it, that leads to problems. Even if you’re dehydrating safe foods, improper preparation can ruin the outcome.

Skipping Blanching for Vegetables

For vegetables such as carrots, broccoli, or green beans, skipping the blanching step results in inferior quality. Blanching:

• Inactivates enzymes that cause spoilage
• Preserves color, texture, and nutritional content
• Reduces drying time

Failing to blanch can lead to faster nutrient degradation and loss of vibrant color, especially in long-term storage.

Overcrowding the Trays

One of the most common mistakes is placing too much food on each tray. Overcrowding reduces airflow, which is critical for even drying. As a result:

• Some pieces dry too fast while others remain moist
• Increased risk of mold in damp spots
• Longer drying times due to trapped moisture

Always spread food in a single layer with space between pieces. If necessary, use multiple trays or dehydrate in batches.

Using Non-Food-Safe Containers or Wraps

If you’re drying purees (like fruit leather), ensure you use only food-safe surfaces. Avoid:

• Plastic wrap not labeled as oven- or heat-safe
• Glass dishes that aren’t tempered and could crack
• Parchment paper that contains silicone coatings not suitable for prolonged heat

Stick to silicone mats, tempered glass trays, or dehydrator-specific fruit leather sheets.

Spices and Additives: Hidden Dangers

Adding flavorings to food before dehydration is common, but not all seasonings or additives are safe.

Excessive Salt or Sugar

While modest seasoning enhances flavor, overly salting or sugaring food can cause issues. Certain preservatives may interfere with moisture removal or encourage bacterial growth if not balanced.

For example:

• Syrups or honey-heavy marinades prevent proper drying by sealing moisture inside
• Overly salty jerky can become unpalatably concentrated after water is removed

Use light coatings and test small batches first.

Wet Marinades Without Drying First

Dipping meat or tofu in a liquid marinade and placing it directly into the dehydrator adds unnecessary moisture. This can:

• Extend drying time significantly
• Lead to uneven results
• Create a soggy, unsafe product if moisture remains

Instead, pat food dry after marinating or use a dry rub for seasonings.

Food Safety Risks and Cross-Contamination

Even with the right foods, safety can be compromised through contamination.

Mixing Raw Meat and Produce on the Same Trays

Many dehydrators come with multiple trays, but using the same trays for raw meat and fruits without thorough cleaning can lead to cross-contamination and foodborne illness. Bacteria like E. coli or Salmonella from meat can spread to fruits, which are often eaten without cooking.

Always:

• Clean trays, tools, and surfaces with hot, soapy water after handling raw meat
• Use separate cutting boards and knives for meat and produce
• Consider dedicating specific trays solely for meat or using disposable liners

Ignoring Storage Practices After Drying

After successful dehydration, improper storage can undo your hard work. Foods left in humid environments or non-airtight containers can reabsorb moisture, leading to mold.

Use:

• Food-grade vacuum-sealed bags
• Mylar bags with oxygen absorbers
• Airtight glass jars in cool, dark places

Test for dryness before storage: The food should be leathery, crisp, or brittle (depending on type), with no moisture when squeezed.

Materials and Equipment to Keep Away from Your Dehydrator

Beyond food items, certain materials should never go near or inside your dehydrator.

Plastic Wrap or Non-Heat-Resistant Films

Covering trays with regular plastic wrap can melt, releasing harmful chemicals onto food. Even if your dehydrator operates at low temperatures, prolonged exposure can degrade plastics not rated for heat.

Always use:

• Dehydrator-specific silicone covers
• Parchment paper (if labeled safe for dehydration)
• Mesh screens for small items without creating a sealed layer

Metal Utensils That Can Scratch Trays

Using metal spoons, tongs, or scrapers can damage plastic or non-stick trays. Scratches not only harbor bacteria but also make cleaning difficult over time.

Use wooden, silicone, or plastic tools designed for food prep to preserve the integrity of your trays.

A Summary Table: What NOT to Put in a Dehydrator

To make things easy, here’s a quick reference table summarizing the key items to exclude:

Final Tips for Safe and Effective Dehydration

To enjoy the full benefits of food dehydration while avoiding risks, follow these best practices:

• Always read your dehydrator’s manual and follow manufacturer guidelines
• Keep the unit in a well-ventilated, dry area away from flammable materials
• Clean trays and components after every use to prevent buildup and odor retention
• Monitor drying times and check food regularly to prevent over-drying or under-drying
• Label and date all dried foods for proper rotation and consumption

By respecting the limitations of your appliance and understanding what not to put in a dehydrator, you can ensure safe, high-quality results every time. Whether you’re making fruit leathers, homemade jerky, or dried herbs, mindful preparation and awareness of risks are the keys to successful food dehydration.

Conclusion

Dehydrators are powerful tools for preserving food, enhancing flavors, and creating nutritious snacks. However, their effectiveness depends on using them correctly. Knowing what items to avoid—whether due to fat content, moisture levels, contamination risk, or inappropriate use—protects your appliance, your health, and your results.

By avoiding high-fat foods, raw eggs, oils, whole produce, and non-food items, and by paying attention to preparation and hygiene, you can get the most from your dehydrator. Keep this guide handy as a reference, and dehydrate with confidence—safely turning your favorite foods into long-lasting, delicious treats.

Can I put raw meat in a dehydrator?

While it is technically possible to dehydrate raw meat, doing so safely requires careful attention to temperature and hygiene. Raw meat can harbor harmful bacteria such as Salmonella and E. coli, which need to be destroyed during the dehydration process. To safely dehydrate meat, it must first be heated to an internal temperature of at least 160°F (71°C) for beef or 165°F (74°C) for poultry before or during drying, depending on your dehydrator’s capabilities.

Improperly dried meat can become a breeding ground for pathogens, leading to foodborne illness. Deli meats and pre-cooked meats should also be avoided unless specifically intended for jerky production using a proper method. Instead of experimenting with unsafe practices, use USDA-approved jerky recipes and ensure your dehydrator maintains a consistent temperature of at least 130°F to 140°F. When in doubt, commercial jerky-making kits or appliances designed for this purpose offer a safer option.

Is it safe to dehydrate dairy products?

Dehydrating dairy products such as milk, cheese, or yogurt is generally not recommended for home dehydrators. Dairy is highly perishable and contains fats and proteins that can spoil quickly, especially at the warm temperatures used in dehydration. The process often results in rancid fats, unpleasant odors, and inconsistent textures, making the final product unpalatable and potentially unsafe.

Additionally, most home dehydrators do not reach the precise temperatures or airflow needed to properly preserve dairy through dehydration. While powdered milk is commercially dehydrated under controlled conditions, replicating this at home is risky and ineffective. Attempting to dry cheese, for example, can lead to greasy residue and mold growth. For these reasons, it’s best to rely on commercially processed dairy powders and avoid putting fresh or soft dairy products in your dehydrator.

Should I dehydrate eggs at home?

Dehydrating eggs at home poses significant safety risks and is not recommended by food safety experts. Raw eggs can contain Salmonella bacteria, and most home dehydrators do not achieve or maintain the high, consistent temperatures needed to eliminate this risk. Even if the eggs appear dry, harmful pathogens may survive, especially if the drying process is uneven or too slow.

Furthermore, rehydrating dried eggs at home can be problematic, as they may not reconstitute properly and can develop off-flavors or textures. Commercially dried eggs are pasteurized and processed in sterile environments, which home setups cannot replicate. If you need powdered eggs for long-term storage, it’s safer and more effective to purchase them from reputable manufacturers rather than attempting to make them yourself.

Can I dehydrate oily foods like avocados or nuts?

Foods high in oil—such as avocados, olives, and most nuts—are not ideal for dehydration due to their fat content. Oils can become rancid when exposed to heat and air over time, leading to unpleasant tastes and potentially harmful compounds. In a dehydrator, these fats are not removed, and the prolonged drying process can accelerate oxidation, reducing shelf life and nutritional value.

Moreover, oily residues can build up on dehydrator trays and internal components, making cleaning difficult and potentially damaging the unit. Avocado, for instance, browns quickly and turns bitter when dried. While some people attempt to dry nut flours or powdered avocado, the results are often inconsistent. Instead, consider storing high-fat foods in airtight containers in the refrigerator or freezer for better preservation.

Is it okay to dehydrate butter or oil-based spreads?

Dehydrating butter or oil-based spreads is not advisable and will not yield useful results. These products are composed mostly of fat, which does not dehydrate like water-rich foods. Instead of drying, butter will melt, pool, and potentially smoke at dehydrator temperatures, creating a mess and a fire hazard. The end product would be oxidized, rancid fat with no practical use.

Additionally, removing moisture from fats doesn’t preserve them effectively, as rancidity occurs through oxidation, not microbial growth. Dehydrated butter would still spoil faster than properly stored refrigerated butter. For long-term storage of fats, consider alternatives like ghee (which has a longer shelf life) or commercially produced shelf-stable fat powders designed for specific uses like baking or cooking.

Can I dehydrate cooked pasta or rice?

Dehydrating cooked pasta or rice is technically possible but not recommended for everyday use due to texture and safety concerns. When rehydrated, these starches often become mushy, gummy, or fail to return to their original consistency. Additionally, cooked grains can develop harmful bacteria like Bacillus cereus if not cooled and dried quickly, increasing the risk of food poisoning.

While some survivalists and backpackers dehydrate pasta or rice for lightweight meals, this requires precise timing and immediate consumption after rehydration. They often pre-cook meals with sauces or seasonings to improve results. For casual users, the effort and risk outweigh the benefits. It’s more practical to store uncooked pasta and rice and prepare them fresh when needed, especially considering the limited shelf life of rehydrated versions.

Should I dehydrate foamy liquids like soapy water or detergent?

Dehydrating foamy or non-food liquids such as soapy water, detergent, or cleaning solutions is extremely dangerous and should never be attempted. These substances are toxic and can release harmful fumes when heated in a dehydrator. Residue left behind can contaminate the machine permanently, posing serious health risks for any future food dehydration.

Dehydrators are designed exclusively for food preservation, not for drying chemicals or household products. Even rinsing the trays may not remove all traces of toxic substances, risking cross-contamination. Always reserve your dehydrator for edible items and keep it away from any non-food materials to ensure safety and maintain the integrity of your equipment.