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How to: Drying insects

Hello openbugfarm!

Since I learned many things from this community already, I want to contribute to it as well by providing my research I'm doing on drying insects. I will be posting every result I have here, including pictures and stuff. If anyone has any tips for me, or a particular insect he or she wants to know how to dry, please comment!

Method: So, I recently bought a food dehydrator, an Espressions Dehydrator EP5600 (€80,-). It can dry at 55, 65 and 75 degrees Celsius (131 F, 149 F and 167 F). I will be putting different kind of insects in the dehydrator at 55, 65 and 75 degrees Celsius for 6, 8, 10 and 12 hours, put them in closed containers and see which ones develop mold and which ones stays allright. I will also be looking at weight(loss), color, form and odor.

Results:

Blaptica dubia

Test 1 So, first insect to test are my own bred B. dubia. I raise these for my reptiles and do not consider eating them at the moment, but who knows, in the future... Setup information is included in the picture below. It also shows how the insects look when dried. I consider this one succesfull! 8 days after this test, '6 HR' is starting to smell funky. This is however what I expected so no big deal. As you can see they lost 63,3% of their original weight!

Note: these B. dubia are rather small, so I'm pretty sure that big, healthier B. dubia will also mold at '8 HR.'

Zophobas morio - Superworm no results yet

Locusta migratoria - Migratory locust no results yet

Tenebrio molitor - Mealworm no results yet

Galleria mellonella - Greater Wax Moth no results yet

Musca domestica - Common housefly no results yet

Hermetia illucens - Black Soldier Fly no results yet

Zophobas morio - Superworm

Test 2 So, after I dried my cockroaches I decided to buy some of the most common feeders and dry those to see how that would go. The reason I only noted 6 hours and 12 hours is because at the 6 hour mark I already saw that this session wasn't going to give me the results I wanted. 75 degrees Celsius is too hot to dry the insects used in Test 2.Setup information is again included in the picture below. Starting weight: 26 grams. Final weight: 8,81 grams. Total weight lose: 66,11%. I will dry superworms again soon at a lower temperature because I think they were dried at a temperature that was too high. I hope to that a lower temperature will just dry them, instead of 'roast' them too.

Locusta migratoria - Migratory locust

Test 2 Once again, information is in the picture below. Total weight loss: 66,23%. Also for these I think the temperature was just too high. They were SUPER crunchy and look somewhat 'roasted,' and they also had a kind of weird odor to them. Will also dry these again soon at a lower temperature.

Tenebrio molitor - Mealworm

Test 2 As usual, information in the picture below. Starting weight: 28 grams. Final weight: 9,41 grams. Total weight loss: 66,39%. Temperature for these was WAY to high. They look burned. Will try these again at lower temperature.

Galleria mellonella

Test 2 Last but not least, my own bred waxworms. I already found out in an earlier test (in the oven at very low temperature) that these would be a pain in the ass to dry. At 6 hours they already started to look pretty messed up (or hadn't changed at all..) and after 12 hours they looked absolutely withered. Will try these again at a lower temperature.

Well, that's it for today. Will do some more tests as soon as possible but this could take a few weeks...

I hope this information is helpful for people looking for a way to preserve their insects by drying them.

With regards,

EntoJesse

Comments

  • @EntoJesse - amazing, we're very excited to see your results! Thank you very much for sharing with the community!

  • how about crickets?

  • @Galuh , crickets I do not know yet, but I will test those in the future. Just like housefly maggots and black soldier fly larvae.

  • Good info, let me know your future tests :)

  • As for the drying tests that were conducted in the end of November 2014:

    It's conclusive to me that drying most insects at 65C for either 6, 8 or 12 hours is not enough. Almost all samples were moldy when I checked them today (so, almost 6 months later).

    However, the samples that were dried at 75C had much better results. Almost all samples were still in good condition even if only dried for 6 hours. The samples that were dried for 12 hours however, looked a bit better to me and showed no signs of degradation whatsoever. All samples done at 75C had not developed any bad odors.

    So, in conclusion, I think it's safe to say that if you dry your insects at 75 degrees Celsius for a period of 12 hours, you can safely store them for 6 months. It could well be that this period can be as long as 12 months or even longer. I will give another update when I reach the 12 month mark.

    I have not been able to obtain any maggots, but I suppose that you could also just dry them at 75C / 12 Hrs.

  • Thx for the Info :) How much energy do you need when drying for 12 hours? And what i thought about, wouldnt the dried insects last much longer if you use a vaccum device and put them in a vaccuum bag?

  • You definitely want to keep dried bugs stored airtight, preferably vacuum sealed to reduce oxidation of the fats. keeping them in a cool dark place (even refrigerated or frozen after drying) will also extend shelf life

  • EntoJesse - thanks so much. just getting started so hopefully i will have stuff to share soon too

  • Excellent thread. I wanted to post some things I've noticed about drying mealworms (tenebrio Molitor).

    I've read online a number of sources saying oven drying is possible, and that it is advantageous to purge the larvae first for two days without new substrate. I recently tested this and found that when cooked at 180 F for 2 hours, they had already taken on that dark - black coloration, and smelled much different than the fresh larvae. The smell is distasteful to me; almost rancid and I wonder if it is due to lipid oxidation. I've noticed a similar smell with a batch of frozen larvae I left on the counter overnight to thaw out. The whole batch turned black and off - smelling.

    I was hoping this would have been solved by purging, because maybe there is some enzymatic reaction that makes the fats rancid, but alas the problem still existed after purging. Also I've dried pupae in the same manner, and they dry beautifully. I thought this might be because they completely purge themselves before pupating. Maybe boiling could also help as a sterilization procedure. I haven't tried this yet.

    I know that lots of marketed dry mealworms are freeze dried. This is what makes me think its an oxidation thing - since freeze drying is done in a vacuum.

    Any suggestions?

  • @double_ott if drying at a very low temp (like 180F) you should boil or otherwise flash-heat the insects first - a kill step should knock out the microbial and enzymatic activity that are degrading the bug during heating. And mealworms do have a lot of fats that can oxidize

  • I read alot about insects that are freeze dried, but are they actually freeze dried with a real freeze dryer? Or is there another method and they just call it freeze drying?

  • @Carni - several companies are using actual freeze drying to dry insects. Note that this is a very expensive option

  • @andrew I tried the flash boil before a low temp bake, and it worked beautifully. I boiled the larvae for 2 minutes, then strained and dry baked at 180 F for 2 hours, and they seemed completely dry, very crunchy, the golden yellow color was retained, and the flavor was still quite good. Thanks for this information - I've been struggling with this step for some time now, and am relieved that it is so simple to dry them without a freeze dryer.

    With a flash boil: https://goo.gl/photos/pKZT4qFE3Svdr33q6

    Without a flash boil: https://goo.gl/photos/paqJ5zVGuhfPo131A

  • @double_ott great! I'm glad that worked so well for you.

  • Is baking them more cost effective than putting them in a dryer? A normal dryer, not a freeze dryer.

  • It's probably a matter of electricity vs natural gas (unless you have an electric oven). I would guess a dehydrator would be more efficient because they have a heating element and a fan, and so probably do the job faster.

  • Have you ever tried lower the temporature and increase the time for heating before ? I guess It could create a perfect shape of insect (They won't be in "dry shape" still look tasty as it was alive) don't you think ?

  • Which method of drying insects on a large scale is most cost effective? My intentions are to sale as is.

  • edited August 4

    Rotary drum drying would allow even slow heat distribution throughout the body masses. I have seen these in developing countries made out of 55 gallon steel drums with a welded crank shaft set in a standing frame with low fires underneath while a person muscles the crank. You could make a low tech version using the principle of a rotating compost tumbler driven by a motor & have a fan blow hot air through one end out the other.

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