How To Dry Silica Gel and Reuse The Desiccant

Silica Gel is an adsorbent, which removes moisture from the air. It can be used to keep the Relative Humidity (RH) of an enclosed space low, and in this way, prevent fungus growth on camera lenses. Over time, Silica Gel becomes saturated with the moisture that it has adsorbed, and loses its ability to continue removing humidity from the air. We need to learn how to dry Silica Gel, to recharge it and make it usable once again.

The process is really easy and I have reused my indicating Silica Gel beads at least a few hundred times over the last decade. The amazing thing is that the Silica Gel continues to work just fine. Let me help you learn everything that you need to know about Silica Gel desiccants, and how you can recharge and reuse your Silica Gel packets for as long as you need, by drying them the correct way!

How to Reactivate Silica Gel:

TL;DR: You can Dry Silica Gel in an oven at 120°C (248°F) for 1-2 hours (see our note about drying time).

There are a few things to be cautious about when you’re drying Silica Gel, so this article will deal with all that information in detail. However, you already have all the practical information you need to dry Silica Gel.

Why Does Silica Gel Need To Be Dried?

When exposed to humid air for an extended period of time, Silica Gel adsorbs moisture, and its microscopic pores become saturated with water. If your camera storage case is not airtight, more moisture will continue to enter it until the silica gel becomes saturated.

Once saturated, the beads will release some of the moisture back into the air, negating the previous benefits. This is why you should keep your cameras and lenses in an airtight box when in storage. It is also why you should dry and recharge your Silica Gel on a regular basis to keep your camera equipment safe from fungal growth.

The good news is that you can easily dry out (or recharge) your Silica Gel beads and use them repeatedly, to keep your camera equipment safe from fungus growth and moisture damage.

How To Tell If Silica Gel Needs More Drying

  1. When Indicating Silica Gel changes color, it is telling you that it is full of moisture. You should recharge it (dry it out) at this point.
  2. Orange Indicating Silica Gel desiccant turns green, and Blue Silica Gel turns pink.
  3. Because normal Silica Gel is white, it is difficult to tell when it has become saturated with moisture. On the other hand, it is easy to tell when Indicating Silica Gel is saturated. This is why I prefer to use Indicating Silica Gel.
  4. If you already have white Silica Gel, you could buy some indicating silica gel, and mix indicating and non-indicating Silica Gel. The Indicating silica gel will help you to judge the condition of all your Silica Gel combined.
  5. Finally, I like to keep a Hygrometer in my camera’s dry box, so that I know what the RH is at all times. When it starts to rise above 50% RH, I recharge my Silica Gel beads

How Much Moisture Can Silica Gel Remove from the Air?

Silica Gel is very efficient at pulling moisture out of the air. It can adsorb up to 37% of its own weight in moisture. This means that every 1,000 grams of Silica Gel can adsorb up to 370ml of moisture from the air around it.

Note that color-indicating Silica Gel changes color when it has gained 8-10% of its weight in moisture. Even if the color changes at 8% of its weight, Silica Gel will continue to adsorb moisture up to 37% of its weight. This gives you a good buffer, so don’t worry if the color of the indicating silica gel has just changed. It’s probably still absorbing moisture even after the color changes, but don’t wait too long.

How Efficient is Silica Gel at Removing Moisture?

At room temperature and high humidity, Silica Gel is remarkably efficient at removing moisture from the surrounding air. It is more efficient at removing moisture from the air at higher humidity levels than at low humidity levels.

  • Silica Gel will reach maximum saturation in about 5 hours at 25°C and 77% RH.
  • As long as the Silica Gel is not saturated, it can reduce RH (Relative Humidity) to less than 40%.

This means that you will get a better result by using more Silica Gel in your dry box, rather than less. I use about 4.5 lbs for a box that is about 6 cubic feet in size because it is quite cheap.

Quick TIP: You can keep track of how humid your camera storage box is, by using a Digital Hygrometer . I highly recommend using one.

How Can I Dry Silica Gel that is Saturated?

Silica Gel can be reused after restoring it to its original condition. Once it is fully dried out, Indicating Silica Gel will return to its original color; either orange or blue depending on its type. At this point, its ability to adsorb moisture is fully restored, and it is ready to be reused.

Spread out the Silica Gel beads, packets, or desiccant packs on a tray covered with a baking sheet, and put it in a preheated oven.

Temperature For Drying Silica Gel Safely

  • Indicating Silica Gel can be heated in an oven at 120°C (248°F) for 1 to 2 hours to dry out the moisture that it has adsorbed. It will return to its original color when recharged.
  • White Silica Gel can safely be heated up to 150°C (302°F) for 1 to 2 hours to recharge it. White Silica Gel does not change color and remains white all the time, so you may want to dry it for a little longer to be safe.

Allow the Silica Gel to cool down in the oven with the door closed, before quickly taking it out, and storing it, or using it in your dry box.

How Long Does Silica Gel Need to Be Dried?

In my extensive experience with drying Silica Gel (maybe I should put that on my résumé?), I have noticed that there’s little point in drying it for more than 2 hours. I, however, didn’t have proof, so I decided to accurately measure the weight of two batches of Silica Gel that I was drying.

Each batch was over 500grams in total, and I weighed each batch before heating, and after 1 hour, 2 hours and 3 hours of heating, each. In this table, I have distilled the data into the percentage of change in the weight of the Silica Gel. As you can see, there is between 14.6%-16.3% change after one hour. After 2 hours, the percent change has reduced significantly to just 4.2%-4.3%. And after the third hour, there’s hardly any change, at just 0.8%-0.5%.

The actual weight reduction ranged from 19.6% after 3 hours for Batch 1, to 21% for Batch 2 when compared to the starting weight.

After 1 hourAfter 2 hoursAfter 3 hours
Batch 114.6%4.2%0.8%
Batch 216.3%4.3%0.5%
Percent Change in Weight Over Time

In summary, the Silica Gel was carrying over 19.5% of its own weight in stored water (over 130grams). After heating the Silica Gel for 1 hour, there was a significant reduction in stored humidity, and less after 2 hours. However, the 3rd hour yielded minimal change, and as a result it is not economical to go on heating Silica Gel for longer. Hence, our suggestion to dry Silica Gel for at least 1 hour, and at the most, 2 hours.

How Many Times Can Silica Gel Products Be Reused?

Silica Gel can be reused up to 500 times or more. Silica Gel’s efficiency decreases after about 100 uses, but it still remains quite efficient at removing moisture from the air almost indefinitely, as long as it is not overheated, and its internal structure is not destroyed.

Caution About Overheating Silica Gel

Overheating Silica Gel to 200°C or higher temperatures will destroy the fine internal structures that suck up moisture. Heating Silica Gel to above 150°C will damage the color-changing indicating chemical. This is why we recommend a safe temperature of 120°C to recharge Silica Gel and instead choose to heat the beads for a longer period of time.

From an environmental perspective, it’s nice to note that Silica Gel can be reused many hundreds of times.

7 Steps to Dry Out & Reuse Silica Gel Repeatedly:

  1. Spread the Silica Gel across the bottom of a bake-safe oven dish (you can use aluminum foil if you prefer to keep it off the dish itself). Spread the beads or crystals evenly and less than an inch deep in the dish.
  2. Place the dish in an oven and heat it to 120° C (248° F) for 1–2 hours until it starts changing color. If you want to avoid the risk of making your Silica Gel inactive, you could use a lower temperature and leave the Silica Gel in for a longer period of time. When the Silica Gel has returned to its original color, it is ready to be taken out.
  3. Do not heat Indicating Silica Gel to more than 125-150° C because it will lose its indicating ability.
  4. Do not heat any Silica Gel to more than 200° C as its fine internal structures will be destroyed.
  5. The Silica Gel beads release the trapped water from within them and will revert to their original blue or orange color. Once the color changes fully, the Silica Gel is recharged and restored to its original capacity.
  6. To speed up the drying process, you can spread the gel out as much as possible, use a fan to circulate air, and periodically move around the Silica Gel layers to dry it out evenly.
  7. Finally, allow the Silica Gel to cool inside the oven, and quickly return it to a sealed airtight container, ready for later use.

Points to Note About Silica Gel:

  • The chemical that actually indicates the presence of water is a little more sensitive, and will most likely turn blue before the Silica Gel is fully refreshed, so keep it in the oven a little longer after the color changes.
  • Remember to use an airtight storage container for long-term storage of your Silica Gel and your camera equipment so that humidity doesn’t keep coming in and saturating the Silica Gel crystals.
  • Remember to recharge your Silica Gel often enough, and your camera equipment should last a very long time.
  • Silica Gel is safe, and you will not die from ingesting the white beads, despite what it says on the packets.

How Much Silica Gel Do You Need For Your Dry Box?

Absolute Humidity Calculation at 40% RH and 25 °C
Absolute Humidity Calculation at 40% RH and 25 °C

Silica Gel quickly absorbs moisture and can hold up to 40% of its weight in water. To keep the level of relative humidity consistently low, it is advisable to use more Silica Gel than may be required.

Silica Gel reduces the humidity of the air to around 40% RH (Relative Humidity), but does not go much below that level.

To calculate how much water must be removed from the atmosphere, we must first know how much is present, then we can calculate how much Silica Gel would be required to remove it. We can do this easily with a Relative Humidity (RH) to Absolute Humidity calculator.

With such a calculator, we can easily calculate how much water is in the air when the Relative Humidity and air temperature are known (easily done with a hygrometer). Then, we can calculate the difference between the current RH and the ideal RH (40% or so), to arrive at the amount of water to be removed, and from there, how much Silica Gel is needed.

Calculation Example:

At an air temperature of 25 °C and Relative Humidity of 75%, there will be about 17.2 grams of water per cubic meter.

In contrast at 40% RH, and the same temperature there will be only 9.2 grams per cubic meter. The difference is about 8g/m3. In this situation, one would need at least 20 grams of Silica Gel per m3 to reduce the relative humidity to 40%, and ideally, one would use more to ensure that any humidity that seeps in is kept under control.

Can a Microwave Oven Be Used to Recharge Silica Gel?

We do not recommend using a microwave to recharge Silica Gel.

Silica Gel adsorbs water vapor into microscopic pores in its structure. Microwave ovens can not regulate the temperature of the materials in them as well as convection ovens. Additionally, the porous structure of Silica Gel shatters when the water evaporates too quickly, and the Silica Gel is no longer able to absorb moisture. When we tried using a microwave oven, the Silica Gel became whiteish and cloudy.

For best results, we suggest using low heat in a conventional convection oven for a longer period of time, as mentioned above.

How to Recharge Silica Gel Without An Oven

So, you don’t have an oven, and we don’t suggest using a microwave… How can you recharge Silica Gel without either? We have some suggestions.

  • Use a small container to hold Silica Gel, and then place that in a larger covered container that has two inches of clean sand inside it. Cover the large container leaving a small gap for moisture to escape, and place it on low heat for 2 hours.
  • Use a pressure cooker without the weight on top instead of the large vessel mentioned above. You will still need the sand.

How Can I Store Recharged Silica Gel?

Storing Silica Gel carefully before it is put to use is vital. If Silica Gel is not stored properly it will immediately start to absorb moisture again.

  • Store Silica Gel in an airtight bag or container after it is dried out. You can use Tupperware, airtight storage boxes, or some vacuum-sealed airtight container.
  • If there is an air leak in the container, it will reabsorb moisture from the air.

If left out in the open, Silica Gel will quickly re-absorb moisture from the air around it and lose its effectiveness. Luckily you now know how to recharge and reuse Silica Gel!

FAQ About Silica Gel for Photographers

1. What Kind of Silica Gel Should I Buy?

Different types of Silica Gel
Different types of Silica Gel

Buy orange indicating Silica Gel beads. They are easy to use, non-toxic, and look nice.

Silica Gel comes in a few different types. Typically they’re sold loose, as crystals, tiny spheres, or in porous plastic sachets that allow air through.

I prefer to buy the loose spheres or crystals because it’s not easy to see the condition of Silica Gel when it is in sachets.

More specifically, I prefer to buy indicative Silica Gel spheres/pellets. This type of Silica Gel is sometimes called reactive Silica Gel.

While they’re difficult to monitor, sachets are very convenient for some non-photographic uses, and to manage humidity in plastic packets.

We recommend that you use Orange Indicating Silica Gel Beads. The orange-to-green type is preferred, as the chemical used to show moisture content is non-toxic and is also less sensitive to heat. The blue-pink indicating Silica Gel contains Cobalt (II) Chloride and is considered carcinogenic in some countries.

2. Is Silica Gel Toxic?

No, Silica Gel itself is not toxic and can even be ingested without causing harm (we discourage you from eating it).

However, the blue chemical is considered carcinogenic when inhaled as a powder. This is why we recommend the orange Silica Gel.

Regardless, you should not try to ingest it or mix it with edible items. Also keep it away from children, eyes, etc.

Additional information:

The Cobalt (II) Chloride used in blue>pink indicative Silica Gel has been classified as hazardous if inhaled or ingested, so if you’re using indicative Silica Gel, don’t inhale the dust from the crystals.

The Orange to Green Silica Gel is considered safe for use.

3. Where Can I Get Indicating Silica Gel?

Personally, I use 2Kgs of orange beads of Silica Gel.

4. What Precautions Should I Take When Using Silica Gel?

Silica Gel itself is safe to handle and use, but here are a few precautions that you can take when using, storing, recharging, and handling silica gel.

  • Silica Gel should not be handled by children, placed near eyes, or ingested. If ingested, Silica Gel is not toxic and will pass through the system. However, they are considered a choking hazard for small children.
  • Do not inhale any dust that comes off Silica Gel. It could cause irritation to the nose and lungs and may cause discomfort if it touches the eyes.
  • When recharging Silica Gel in an oven, it may remain hot for quite a while. You can allow it to cool down in the oven until it is safe to handle and then transfer it to an airtight sealed container for long-term storage.
  • Orange Silica Gel – Comprehensive Safety Information.

5. How Can I Use Silica Gel, & Why Is It Important For Photographers?

Silica Gel can be used to remove condensation that is inside camera lenses, and is important when storing cameras in humid environments.

Camera equipment needs to be stored under low humidity or else it becomes possible for fungus to grow on the elements of lenses. Additionally, high humidity also causes rubber parts of the camera and lens to begin degrading.

Silica Gel is, therefore, a very important part of camera maintenance, both in the short and long term. Knowing how Silica Gel works and is recharged is important for photographers to be able to take care of their equipment.

What is Silica Gel?

Silica gel is a naturally occurring compound that is a type of amorphous silicon dioxide. It’s made from quartz sand, a crystalline form of silicon dioxide. The gel form of silica gel is created through the precipitation of a silicon dioxide solution in water.

The silica gel used in industries is a synthetic product created in a laboratory. It is a form of silicon dioxide that is insoluble, porous, and highly cross-linked. The gel is used as an adsorbent, desiccant, and catalyst support.

The main advantage of silica gel is its high adsorption capacity. It can adsorb up to 40% of its weight in water vapor. The gel is also resistant to mold and bacteria. It is non-toxic.

The gel is available in different forms, such as beads, granules, and powder. The beads are the most common form of silica gel. They are round and have a uniform size. The granules are irregular in shape and have a larger surface area than the beads. The powder form of silica gel is the most fine-grained form of the gel.

What Can Silica Gel Desiccant Packets Be Used For?

Here are some ideas for how to reuse Silica Gel desiccant.

  1. Moisture protection: Silica gel packets are often included in the packaging for electronics, shoes, and other items that are sensitive to moisture to help keep them dry. It prevents rusting of metal and corrosion of electronic components in humid conditions, as well as mold and mildew on leather and other organic material. You’ll see it used in:
    • Camera Bags and Dry Boxes, to prevent lens fungus from affecting your images.
    • Gun Safes and ammo boxes; to prevent rust.
    • Storage of Seasonal Equipment, Clothing, and Accessories like camping gear, winter clothing, and accessories like luggage and purses.
    • Shaving kits, to prevent razor blades from rusting, and electronic components from corroding.
    • Minimize water damage to cellphones once they’re dropped in water. Silica Gel is much more effective than rice in quickly removing any water and humidity from a phone’s interiors without opening up the phone.
    • Prevent Jewelry, Silverware, and Brassware from tarnishing. It can be used to keep dinnerware, jewelry, coins, and other valuable metalware free of tarnish for longer.
  2. Deodorizing: Silica gel packets can be placed in closets, drawers, and other small spaces to absorb moisture and help eliminate unpleasant odors. The porous nature of silica gel allows it to absorb moisture from the air, which can help reduce the relative humidity in a closed space and prevent the growth of mold and mildew. In addition, silica gel can absorb and trap odors, helping to freshen and deodorize the air in small spaces.
  3. Gardening: Silica gel can be used to help preserve seeds by absorbing excess moisture and helping to prevent mold, rot, and mildew. This can be especially useful for storing seeds over long periods of time or in humid environments where these conditions may be more likely to occur.

    To use silica gel for seed storage, you can place a small amount of the gel in a container with the seeds and seal the container tightly. The silica gel will absorb any excess moisture in the container, helping to keep the seeds dry and preserve their viability. It is important to make sure that the container is sealed tightly to prevent moisture from entering and that the silica gel is replaced as needed to maintain its moisture-absorbing capabilities.
  4. Medical uses: Silica gel packets are sometimes used in medical and laboratory settings to help keep medications and other sensitive materials dry and free from contamination. It is used in Drug Packaging, where the material may be sensitive to moisture, in the storage of sensitive medical devices, it’s used in labs to keep samples and specimens dry, well preserved, and free from contamination.
  5. Food storage: Silica gel is not toxic, so Silica gel packets can be placed in food storage containers to help keep food fresh and dry. It effectively protects food items from mold and can extend the shelf-life of many perishable foods. Take care not to consume the Silica Gel itself.
  6. Preserve Old Documents, & Artifacts: Silica Gel is used extensively in preserving documents and artifacts that are displayed in museums and exhibitions. This is because it is able to maintain a stable level of humidity over long periods of time.
  7. Drying Flowers: Silica Gel is used to dry out and preserve flowers for arrangements in as little as a few days to a week. The result is that the dried flowers retain their beauty for extended periods of time. The desiccant beads can be recharged and reused to dry flowers a few hundred times, regardless of whether you choose the indicating or non-indicating (white) varieties. They’re non-toxic and completely safe.

Finally, remember that while silica gel can be used extensively, it also needs to be recharged at the right time to maintain its moisture-absorbing properties. On you go, to create amazing things once you learn how to dry desiccant packets!

Reference Material

Now that you have read right through to the end, follow this link if you want more information about how to take care of your cameras when it’s raining, or if you live in a humid area.

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Susheel Chandradhas

Susheel Chandradhas

Susheel Chandradhas is a Product Photographer and Filmmaker based in India. He has been taking photographs (almost) all his life. He has a diploma and a bachelors degree in Visual Communication, where his classmates all believed that he would write a book on photography... Instead, he writes on this website (because - isn't a community more fun?).

His passions include photography, parkour, wide-angle lenses, blue skies, fire extinguishers, and fast computers.

In addition to writing for Beyond Photo Tips, Susheel is a staff writer for Fstoppers.com, and owns and runs ColoursAlive, a photography, and video production studio.

You can connect with Susheel on Twitter, Instagram, or LinkedIn.

Articles: 144

14 Comments

  1. Hi Susheel, recently acquired a new dry cabinet wth digital indicator outside ,but has a manual setting inside the cabinet ,which is set for RH of say 43 %.Is such type of dry cabi.is any way less efficient than the one called ‘digital’,which has controls outside the cabinet?I wl have to ,anyway,open the cabi.to get my gear out ,right?So whats a big deal of having control outside?
    Pls xplain d diff.I am confused..I already invested in a ‘manual’ Dehumidifier.Regards.Dr.Mhatre

    • Hello Dr. Mhatre,

      Thanks for stopping by and leaving your comment. From what I understand, the efficiency of the dehumidifying mechanism would not vary much based on digital or manual controls and / or their placement. Usually, digital controls do offer more fine-grained control over the RH that is maintained, turning the mechanism off and on more frequently than analog controls. PS: these cabinets do not need to have their settings changed once set. They’re essentially set-and-forget. 40% seems like a good place to keep the RH. I don’t think you should ever need to change it. So based on that, you could decide to get the one with the controls inside the cabinet, or outside. Do let us know what you decide to do. Your insight could prove valuable to others. Thanks :D

  2. good day for all,
    i would like to ask about the optimum way to use silica gel blue(2-4 mm) as a dryer, what is the required quantity to the suitable area, humidity, ….
    thanks

    • Hi Ahmed,

      While there are some research papers that talk about how much silica gel to use per x volume of air for long term storage, these papers are directed towards use for museum showcases, and for the preservation of manuscripts and other fragile items. I’d suggest that you should decide the relative humidity level that you want to maintain, then get a hygrometer to check the actual humidity of the space. Experiment so that you’re able to maintain a humidity level that you’re comfortable at. I personally put about 100 grams of the orange balls into a perforated plastic container to get the humidity out of a 2x4ft box. I change the silica gel beads every week or two. I think that it has worked for me so far.

      Hope that helps.

      Susheel

  3. i agree with this article. Working with Sorbead India in this industry have opened my eyes as to how vital are those silica gel packets.

  4. I was just curious if anyone has ever tried using an air fryer to recharge desiccant?
    Or if you think that may be a suitable methods?

    • Hi Adam, Not having used an air fryer I couldn’t really tell you for sure. A quick search shows me that Air Fryers typically operate at 200 Degrees Centigrade. This is too hot for Silica Gel, which needs about 100 Degrees Centigrade. If yours has a variable temperature that goes down to 100 Deg Celcius, you can definitely give it a try. Let us know what happens. :) Thank you for stopping by and commenting.

  5. i am using white silica gel. but i am confused when to recharge it. does it turn in any color when it needs to recharge or is there any other way to get to know…?

    • Only Indicating Silica Gel changes colour when it is saturated. This is usually coloured orange/yellow or blue. If you have white, colourless Silica Gel, then there’s a chance that you will saturate it without knowing so. I’d suggest buying some Indicating Silica Gel as soon as you can.

  6. I have one air tight dry box with analog humidity indicator. But I also buy 2 digital type too. I know that lowest and highest value is differs one to another. But when it indicate some stable condition in the middle of range. they also indicate quite differ value, For example, 2 different brand digital humidity indicator indicate 26%and 47%, while analog indicator indicates 65%, Silica gel already had turned to pinkish color. Which value should I believe. Which brand of humidity indicator more accurate?

    • That’s a great question and one that I should probably investigate in a different article. However, for the moment I think you should believe your Silica Gel.

      If the Silica Gel is pink, it is already time to recharge it. Don’t leave it in your dry box. I would investigate whether you should use a bit more of Silica Gel – if it is getting saturated quickly.

      I understand that your box is airtight, so it shouldn’t be getting saturated if you’re not opening it often. If you do open it often, remember to recharge the Silica Gel in a timely manner.

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