Rice as a dessicant study

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22

You could control for dust by putting the rice in filter bags or moisture membrane, similar to what’s used in the construction of silica gel sachets. A number of desiccates are fragile and can produce dust when mechanically agitated and/or through regeneration, or so I’ve read, so the dust issue is not limited to only rice.

However, rice is certainly cheap. Currently $26 for a 50 pound bag at Sam’s Club. A more direct comparison on effectiveness would be interesting. As a first layer defense, maybe it might even win on economics. If there’s anything more definitive, count me as interested. I posted in a different thread about certain types of kitty liter being essentially the same as silica gel, but more economic. Why more economic? Economies of scale? Differences in purity? Not really sure why. No one on the forum here seemed interested in that as an alternative, however. Maybe because bog standard silica gel desiccant isn’t really all that expensive in the first place.

Something you may not know: usual regeneration temperature for silica gel is in the range of 100 - 150C. Allegedly the indicator colorant can get damaged at the higher end of that temperature range, though, and the effect is cumulative. Also, the silica gel itself can also get more damaged at the higher end of that range. So, for silica gel preservation, the recommended max may be 120C. For the most colorant preservation, I’ve read the max is 100C. Exposure time at temperature is a factor as well in how much damage may get incurred. This is pulling from just general google searches, though, rather than anything I would call scientifically definitive, so maybe you all may know of better regeneration guidelines than what I’m quoting here…

23

Aside from comparing notes, I guess I no longer even need to ask such questions on a forum anymore. Putting the question to the new alpha release of chatgpt, it sounds as though rice is probably a waste of time:

Thought for 10 seconds

Comparing Dried Rice and Silica Gel as Desiccants

When it comes to moisture absorption, both dried rice and silica gel are used to reduce humidity in enclosed spaces. However, their effectiveness varies significantly due to their differing properties.

Moisture Absorption Capacity

  • Silica Gel:
    • High Absorption: Silica gel can absorb up to 40% of its weight in moisture.
    • Porous Structure: Composed of silicon dioxide, it has a vast network of pores that trap water molecules efficiently.
    • Consistency: Provides reliable and predictable moisture absorption over a range of humidity levels.
  • Dried Rice:
    • Low Absorption: Rice has a much lower capacity to absorb moisture compared to silica gel.
    • Limited Efficiency: It lacks the porous structure that makes silica gel effective, resulting in slower and less significant moisture uptake.

Speed of Moisture Absorption

  • Silica Gel:
    • Rapid Action: Begins absorbing moisture immediately upon exposure.
    • Effective Over Time: Maintains absorption efficiency over extended periods.
  • Dried Rice:
    • Slow Process: Takes considerably longer to absorb minimal amounts of moisture.
    • Inefficient for Quick Drying: Not suitable for situations requiring rapid dehumidification.

Reusability

  • Silica Gel:
    • Regenerable: Can be dried out and reused multiple times by heating it to release absorbed moisture.
    • Cost-Effective: Longevity makes it economical for long-term use.
  • Dried Rice:
    • Single-Use: Not practical to dry out and reuse.
    • Potential for Mold: Can develop mold or bacteria if it becomes damp, posing a risk to stored items.

Practical Applications

  • Silica Gel:
    • Versatile Use: Ideal for protecting electronics, documents, clothing, and other valuables from moisture damage.
    • Controlled Environment: Often used in packaging to maintain product integrity during shipping and storage.
  • Dried Rice:
    • Home Remedies: Commonly believed to help dry out wet electronics, though effectiveness is limited.
    • Not Recommended for Electronics: Rice grains can get lodged in device openings, and its dust can contaminate components.

Safety and Cleanliness

  • Silica Gel:
    • Non-Toxic (When Indicated): Most are non-toxic, but some contain cobalt chloride (a moisture indicator) which is toxic if ingested.
    • Dust-Free: Packaged to prevent dust release, keeping items clean.
  • Dried Rice:
    • Food Product: Can attract pests like insects or rodents when used in storage.
    • Mess Potential: Rice grains and dust can spill, creating a cleanup issue.

Conclusion

Silica gel outperforms dried rice as a desiccant in virtually all aspects—absorption capacity, speed, reusability, and practicality. While rice may have some minimal moisture-absorbing properties, it is not efficient or effective enough for reliable use as a desiccant. For tasks like preserving electronics, documents, or other moisture-sensitive items, silica gel is the superior choice.

Recommendation: For optimal moisture control, use silica gel or other commercially available desiccants designed for effective humidity absorption.

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24

Seems complete BS to me. Have dried out and reused rice multiple times for other applications. But we’ll find out- read my following post. And letting it get damp will not happen as a hygrometer in the chamber will let you know when you’re rice is not absorbing efficiently. That happens before it’s damp. Rice gets damp when something has actually wet it.

  • Food Product: Can attract pests like insects or rodents when used in storage.

Sure, if it’s stored out in the open in an unsealed bag. In a Bento box inside an AMS?
Highly unlikely

25

So,

With all the “well they say”, and “it says here”, this is what I’m doing.

Have ordered an insertions hygrometer used for testing humidity in soil, materials, and solids.

Will buy 3 bags of rice (2lb bags) from different manufacturers and get the original humidity as shipped in each one.

Will then dry half of each bag at 120 F for 8 hours in a dehydrator and test each one.

Will then dry the other half at 2 degrees below boiling and test each one. The reason for 2 degrees below boiling instead of 212 F is because the boiling point at my altitude is 200.6 degrees. Silica gel drying is recommended to be 210 degrees at sea level, i.e. 2 degrees below boiling.

Will then set them out and see at what percentage they saturate. Will also track external humidity with equipment I already have.

Just so you know this won’t be done using shade tree mechanic methods. My background is what’s called an Instrumentation and Controls technician. I have 40= years in the field, multiple factory training certifications including temperature, flow (multiple technologies), chemical analysis (pH and other parameters), humidity, level (like hydrostatic, radar, ultrasonic and others), and numerous other measurements. I’m also trained in factory calibrations of all of these measurement types. Half of my job involves testing and troubleshooting. I’ve even written calibration and testing procedures for measurements in the pharmaceutical and nuclear industries which have based detailed audits (as have the actual calibrations I’ve performed).

So between now and then, I will fully develop the methodology. My only restriction is I do not have a humidity controlled chamber I can use to maintain a constant humidity for the saturation test. I do however, have a highly accurate atmospheric RH meter and a datalogger I can connect it to.

Will dry the rice out after it reaches saturation and report the results, then run a second saturation test on it.

Will find out where things land when this is complete. I’m expecting the saturation test to take quite a while with doing it twice.

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26

I’m eager to hear about your findings. This is exactly the kind of hard empirical data that is seen far too seldom in this field. It’s good to know that some folks are still willing to roll up their sleeves and offer data from actual measurements rather than just opinion. :+1:

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27

I have saved two phones that got wet with rice.
Like are you grinding up the rice into flour first.
The USB port is the only real place you could potentially get rice stuck.
A bowl of rice covering the phone has saved two phones and worked just fine after 6 hours or so.

It would suck for drying filament unless you like wasting large amounts of rice .

28

Oh, and so you know, the desiccant in my AMS is saturated. Will replace it with rice. While all the other testing is going on, will let you know how it performs, as I ordered the hygrometers BL sells. Got them from Amazon for quick delivery, the insertion meter won’t be here until the end of October.

Out of curiosity will work the insertion probe into a filament spool, then seal the whole spool in a bag and see if I can get a material reading off it.

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I’m just a reporter, reporting information as I find it.

I personally have never used rice. I always have access to desiccant though.

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image

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31

@Quietman

Bravo: the more eyes on the prize, the better.

Waiting with baited breath for the results.

33

Makes sense. So, if @Quietman proceeds with his experiment, he should obviously “charge” his rice first. To that end, I asked chatgpt for a procedure to accomplish that, and here is its advice:

To enhance the effectiveness of rice as a desiccant, it should be “charged” or prepared by removing as much moisture as possible. This process is relatively simple and involves drying the rice to increase its moisture absorption capacity. Here’s how you can do it:

Steps to “charge” rice as a desiccant:

  1. Use uncooked white rice: White rice is better than brown rice because it has less oil content, which means it’s more effective at absorbing moisture.
  2. Dry the rice in the oven:
  • Preheat your oven to a low temperature, around 120°C to 150°C (250°F to 300°F).
  • Spread the rice in a thin, even layer on a baking tray. Make sure the layer is not too thick to allow even drying.
  • Bake the rice for 1 to 2 hours. Stir the rice occasionally to ensure even drying and avoid burning.
  • Once done, let the rice cool to room temperature.
  1. Store the charged rice: After the rice is fully dried and cooled, immediately transfer it to an airtight container or a sealed plastic bag. This prevents it from reabsorbing moisture from the air before you use it.
  2. Use the charged rice: Place the charged rice in small, breathable bags (like muslin or cheesecloth) to absorb moisture in the desired environment (e.g., in a box with electronics, a camera bag, or a container for dry foods).

By removing moisture from the rice in advance, you allow it to absorb more water when it’s used as a desiccant. While rice is not as efficient as commercial desiccants like silica gel, “charging” it in this way will improve its effectiveness.

Hope that helps!

It would seem the best hope for this having a positive result would be to compensate for the inefficiency of the rice by utilizing vastly more quantity. I’ve no idea what the breakeven point would be as compared to silica gel, but maybe our entrepid @Quietman can calculate it based on measurements he gathers. Maybe you’d have to literally bury your filament in charged rice to afford it protection. Who knows?

34

I admire the experiment that @Quietman is about to undertake as much as I admire the patience to do it.

I have none.

To me, the unscientific and mentally challenged, it either works or it doesn’t. Desiccant is better or not. Seems like a hydrometer and closed container will give you the black and white answer.

35

Two other readily available hygroscopic materials, which you may also want to test, are common table salt and natural honey. Honey could be interesting for drying filament, but it is often used on bandages for drying wounds, as an antiseptic, etc.

38

I do not need a scientist to tell me about global warming. It is apparent to anyone that it has been warming since the last Ice Age. What is in issue is how much man is contributing to the warming at this stage. That is where the personal goals of scientists can conflict with reality. The idea that scientists are unbiased is laughable at best.

39

Hold on their pardner… I object to your characterization of it being “Global warming”. My wife – who is always cold – prefers to call it “Global Comforting”. :rofl:So let’s not confuse the two. :grin:

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What bias are scientists carrying?

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All I know is that in general MZip has made a lot of worthwhile posts to the forum, and I wish we had another dozen people like him. But we don’t. And now he seems to have left, possibly over frustration with this thread, so it’s a net loss.

Let’s draw a line under it and move back to the OG topic for the sake of those who are interested in it.

For those who want to talk more about global warming, I suggest starting a separate thread in the “other” section of the forum and continue there. Otherwise this will go off the rails.

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42

This pisses me off.

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43

I agree whole heartedly.

I hope this is not true. I just saw him posting yesterday. It would truly be a loss if he did leave.

If he’s reading this, I want him to know that people here have shown they appreciate his contributions, even if a few don’t know how to respectfully disagree. Having dealt with that kind of toxicity myself, I completely get how it feels when your heart’s in the right place, but someone ruins it for everyone else. The challenge with written communication is that it’s hard to convey intent and subtleties that in-person body language provides, which can often lead to misinterpretation and unintended hurt feelings. But such is the place we call “The Internet”. :worried:

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Scientist’s biases run the full spectrum, from insanely liberal to crazy conservative and all points in between. Before they became “scientists” they were people. After they became “scientists” they were still people. People are defective in case you have no noticed. They have likes and dislikes and will flavor everything they do in an attempt to improve what they consider to be the best course of action. Only immature people believe that judges, scientists, et al are unbiased. Or a fool.