What filling makes the best hot pack? A comparison of hot pack fillings.

hot-pack-fillings

So the weather is starting to get cold and it’s time to bring out the hot packs in my house! I have several hot packs in various shapes and sizes for warming me up or soothing sore muscles over the winter. I also love to gift hot/cold packs. It is just something everyone can use!

A few years ago when I made my first hot pack, I filled it with lentils, which smelled terrible when heated. I then switched to barley, which was better but still a bit meh. The last few years I’ve been very enamored with cherry pits as a filling for my large hot packs, but I’ve always wondered about the differences between fillings. I thought it would be a fun experiment to try out all of the possible fillings I could find in my house and also make a dozen handwarmers.


Note of caution: when researching this post, I came across many people complaining their hot packs burned or started to smell really bad after heating. It is absolutely essential to put a mug with some water in it in the microwave at the same time as you heat your hot pack. Without it your pack could possibly burn or catch fire, and you can damage your microwave. If you give hot packs as a gift, be sure to mention this to your giftee!

When heating a new hot pack, heat it up in 30-second intervals, testing after each, until you learn how long it takes to heat up your pack without scorching it. The fillings below all varied wildly with how long they took to heat up, so it’s not only the volume of filling that affects the heating time, but also the type of filling. And some fillings, like corn, get way too hot if you heat them too long.


hand-warmers

So, I tested (sources at the end of this post):

  • cherry pits
  • wheat berries
  • whole dried corn (feed corn or bird seed, not popcorn!!)
  • pot barley (can substitute pearled barley)
  • dried whole peas (can substitute split peas)
  • buckwheat groats (can substitute buckwheat hulls)
  • whole flaxseed
  • jasmine rice (basmati is another very fragrant rice)
  • steel cut oats
  • clay gardening beads
  • coarse crushed walnut shells
  • dried pinto beans

For each of the handwarmers I sewed two 5″ squares of heavier-weight cotton/linen fabric right sides together with cotton thread, leaving a 2-inch opening along one side. Then I turned the fabric right side out, poked out the corners, and filled it with about 1 scant cup of filling. I whipstitched the opening shut.

It is important to use 100% cotton or linen for anything that will go in the microwave. If you’d like to use fleece or another synthetic fabric, sew an inner cotton bag for the filling, and sew an outer cover with the fleece to slip on after heating the cotton bag.

I found the bags had a little bit nicer weight by making them from a home dec-weight fabric, but you could also use flannel, or two layers of fabric. I’ve seen many hot packs that have a quilted cover and as long as you use 100% cotton batting that works too!

hot-packs-2


The results summary, for those who don’t want to read through the data:

  • Best overall options: Whole corn, walnut shells, jasmine rice. I still love cherry pits for larger packs, but their heat doesn’t last in a small pack. My daughter suggested adding some cherry pits to another filling; I tried 1/4 cup mixed in with corn and that made it smell lovely without the rapid heat loss. My choice would be either the corn/cherry pit mix or walnut shells.
  • Worst options: Buckwheat hulls (too expensive), clay beads or cherry pits (poor heat retention in a small pack), dried pinto beans or whole peas (beany smell), or flaxseed (even after a few heatings the oils were starting to smell a little rancid). However, flaxseed would probably make an amazing cold pack if you kept it in the freezer.
  • Best smelling: Cherry pits, jasmine rice, or walnut shells. If you choose a different filling, you can make it smell nicer by mixing in essential oils, dried flowers, dried herbs, or cherry pits.
  • Most pleasant feel: Flaxseed, whole corn, jasmine rice.
  • Best heat retention: Whole corn, rice, wheat, walnut shells.
  • Can be washed and dried and won’t mold or degrade: Cherry pits, clay beads, walnut shells. All other fillings will need a removable cover if you’d like to be able to wash your hot pack. All food-based fillings will degrade over time and need replacing. The sturdier ones like whole corn will last longer than things like rice or grains.

 

Table of results:

Filling Weight /
price
per cup
Feel Smell after heating Heat retention
Cherry pits 100g / $0.34-$1.32 Large, chunky, awkward. Pleasant sound. Lovely cherry pie Poor in such a small hot pack
Wheat 182g / $0.33 Small & grainy Grainy, neutral Average
Feed corn 181g / $0.03 Large flat, slippery chunks. Pleasant sound. Faint corn Good, heats very quickly
Barley 187g / $0.37 Small & grainy Grainy, not as strong as wheat Average
Whole dried peas 173g / $0.44 Little spheres Beany, not great Average
Buckwheat hulls/groats 168g / $1.19-$0.59 Pointy, not as slippery Earthy Average
Whole flaxseed 150g / $0.44 Slippery, smooth, luxurious Oily. Oils go rancid and over time the smell might get bad. Would probably be fabulous as a cold pack that is kept in the freezer. Good, heats very slowly
Jasmine rice 188g / $0.33 Rice-y, satisfying creaking sound when squeezing, stiff Lovely and fragrant Good, heats quickly
Steel cut oats 162g / $0.37 Smaller & grainy Grainy. Not as strong as wheat Average
Clay beads 102g / $0.11 Large, irregular, not slippery. Very awkward. None Terrible
Crushed walnut shells 143g / $0.07 Small and a little crunchy; use less filling if you want it to conform Sweet & nutty, a little like marzipan Good, heats very slowly
Dried pinto beans 182g / $0.33 Large and somewhat slippery with a flat surface, similar to corn. Beany, not great Good

 

If you’re looking for a unique hot/cold pack to gift (or keep!) this holiday season, check out my Comfort pack pattern, which is a hot/cold pack in the shape of a hot water bottle.

Comfort pack pattern

 


Notes on suppliers: Most items above are available at a grocery store, and the cheapest prices will be in the bulk section. I actually found 11 out of the 12 items above in my house already! I only had to purchase the white rice.

  • The cherry pits I purchased at cherrypitstore.com. The price difference in the table is the small bag vs. the large bag and includes shipping costs.
  • The whole peas I bought at an Indian grocery store, You can substitute split peas for the whole peas, they will just have a slightly different feel.
  • The corn I also bought at an Indian grocery store, but you can use feed corn from a farm supply or birdseed supplier. Feed corn is only about $7.50 for a 50 pound bag at places like Fleet Farm, so use what you need from the huge bag, and then put the rest outside to feed birds and animals.
  • Buckwheat hulls are sold on Amazon and in other online shops.
  • Clay beads are hydroponic gardening beads I had leftover from a lettuce growing experiment.
  • Crushed walnut shells are available at any pet store as lizard bedding. I used a very coarsely ground one, but I would think the finely ground stuff would also work just fine. Use a very small stitch length to avoid too much leaking!
2017-01-13T04:45:20+00:00 December 2nd, 2016|

72 Comments

  1. Veggiesandberries December 16, 2016 at 10:06 pm - Reply

    I like plain cheap rice and buckwheat hulls and can’t wait to try the walnut shells! Thank you for doing all the testing!

  2. lila heide January 19, 2017 at 3:04 pm - Reply

    I use grape seeds. They keep the heat well and smell like freshly baked bread.

  3. Christie Lancaster September 29, 2017 at 9:30 pm - Reply

    Thanks for the research and all of the effort you put into it. So I know this may will be a crazy question, Can you use couscous in them?
    I’ve never cooked it, never tasted it, but some how have ended up with several bags of it from my daughter. It appears like it would do well in them, but will it actually “cook” when heated? Like I say I’ve never cooked it so,
    Does it put off an odor at all?
    Just wondering, I hate to see all of it go to waste, so fingers crossed.
    Maybe I stumbled into something great, or maybe I tripped and landed in a big ol pile of
    uncooked couscous,

    • CrispyKristin October 4, 2017 at 10:15 pm - Reply

      I would think that couscous would go moldy. If it got even slightly damp it wouldn’t be usable afterwards.

    • Pascale November 19, 2017 at 9:39 am - Reply

      I have never tested it but couscous cooks in 5 minutes in boiling water so I would imagine it would cook or go soggy if there’s the recommenced mug of water in the microwave with the pack.
      Also, couscous is delicious, quick and lasts forever so I’d go for the yummies!

  4. natasha October 15, 2017 at 2:45 pm - Reply

    Last year i used the feed corn. Where im at i had to buy in a large 50lb bag and no where to take the left overs, little did i know i soon had an infestation of grain weevals. Just a warning to those going this route that if you have to buy in bulk have a back up plan for the left overs and/ keep it out doors. Today i opened one of the bags and weevals were in it and about 50% of the feed was rotten. Id definitely suggest changing it out. I am now looking for a non grain substitution. Thank you for posting your findings. I am going to try the clay beads now.

  5. Granny November 7, 2017 at 9:10 pm - Reply

    Wondering if anyone has tried thistle seed?

  6. Rachel November 10, 2017 at 4:34 pm - Reply

    what exact brand of coarse ground walnut shells did you use? is the lizzard bedding stuff too finely ground?

  7. Denise November 18, 2017 at 2:35 pm - Reply

    I want to add essential oils, which one would hold the scent better?

    • CrispyKristin November 18, 2017 at 3:54 pm - Reply

      I’m honestly not sure which would hold their scent best. I would think you could always add a drop or two to the outside of the pack at any time to refresh the scent, though!

  8. Nanette Sparks November 18, 2017 at 4:14 pm - Reply

    Could I use cherry pits from cherries I purchased or do they have to be dried out or treated for a certain amount of time before being used?

    • CrispyKristin November 19, 2017 at 9:44 pm - Reply

      I tried that, and it is actually very difficult to get all the fruit off of the pits, and you’d have to eat a LOT of cherries to get enough pits for a larger pack. So much easier to leave the gathering and cleaning to someone else! 🙂

  9. Amanda November 19, 2017 at 12:38 pm - Reply

    When washing with one of the approved list above, is it best to hand wash/gentle cycle, and should it air dry or can you throw it in the dryer?

    • CrispyKristin November 19, 2017 at 9:45 pm - Reply

      If you’re washing cherry pits, I would think to do a gentle wash and then dry in the dryer so it is for sure dry and doesn’t get moldy. I wouldn’t wash any of the other fillings.

  10. Breanne November 22, 2017 at 2:53 am - Reply

    This post answers so many questions I’ve had for so long! Thank you for all your work. I’m looking into making a weighted blanket for my husband where you can remove sections to heat them up and then put back into the blanket. I’ve seen some sites recommend heavy-duty polypropylene plastic pellets for the blankets. Some of the comments say they are a high enough grade plastic that they can be microwaved, but I am nervous to try. Do you have any experience/insight into using these pellets? Example here: https://www.amazon.com/gp/product/B01HLA2HA2/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&tag=givohgiv-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B01HLA2HA2&linkId=57ef9807eaab07ff20ed6bb59b23f03b

    • Breanne December 16, 2017 at 8:15 pm - Reply

      Just to follow up… I contacted the seller of the polypropylene pellets to ask him about microwaving. He told me they can be microwaved without any problem, but that their heat retention isn’t as good as other materials. Hope this helps anyone else with the same question.

  11. carol spencer November 22, 2017 at 9:33 pm - Reply

    I’ve also tried many fillings but now only make them with jasmine rice,.This gives a wonderful scent! heats up quickly and has enough moisture in the rice ( naturally) to provide a moist heat

  12. Julie Richardson November 26, 2017 at 12:45 pm - Reply

    Rice and dried mint leaves are great. I have then making these for years and have never had a problem

  13. Kayla J November 27, 2017 at 3:55 pm - Reply

    Thank you for doing this experiment! I’ve been wondering what I should fill my hand warmer presents with and this is a very extensive table. I appreciate your hard work and organization in this post!

  14. Kelsey Sawyer December 1, 2017 at 12:48 pm - Reply

    Have you ever mixed walnut shells with rice? I was trying to think that would be cost effective but i didn’t know your experience in mixing the fillers.

  15. Cynde Johnston December 5, 2017 at 5:27 am - Reply

    Thank you for all the research. I have always just used plain rice but started using flaxseed after reading they hold their heat better because if the oil content. I didn’t feel that was true so my daughter and I tested that idea for a grade school science fair. We compared golden flaxseed vs black flaxseed vs plain rice. The black flaxseed heated to the highest temp out of the microwave but also cooled off faster. The rice won by having a higher heat at the 15,30, and 60 minute times. I will spend the extra money for the jasmine rice after reading all the comments. Thanks again!

    • Claire December 15, 2017 at 7:16 am - Reply

      Thank for sharing this wonderful informacion!

  16. Cynde Johnston December 5, 2017 at 6:24 am - Reply

    Forgot to mention, flaxseed does make an amazing cold pack. 8 oz in an eye pillow will be 29-31 degrees after 1 hour in the freezer. Perfect for boo boos, itchies, or a cold headache compress. Can also be kept in the fridge.

  17. Arlene Roy December 7, 2017 at 4:55 am - Reply

    Thank you for your research. I will use walnut shells – had a rice one and a mouse got into it. Bet he had a feast!!

  18. Barbara Zacchigna December 11, 2017 at 9:42 pm - Reply

    Wouldn’t whole corn pop? Or is that a different kind?

    • CrispyKristin December 13, 2017 at 6:19 pm - Reply

      Popcorn is a different thing than feed corn. Feed corn doesn’t pop.

  19. Lisa December 14, 2017 at 4:19 am - Reply

    I made some of these using flax seed in the past. I added a mixture of orange peel, cinnamon, cloves and eucalyptus to some, and lavender and rose petals to others. They were a big hit! I was thinking of doing these again with rice now that I have read your research. I would add a few drops of essential oil to my mixtures this time.

  20. Megan December 14, 2017 at 5:17 am - Reply

    I bought feed corn at the local feed shop, but it’s very “dusty”. Is it safe to rinse them and let them dry back out before using them in a pack? Is it even necessary?

    • Heather Cool December 14, 2017 at 4:28 pm - Reply

      Yup, rinse it in a colander, and then spread it on a (parchment lined) baking pan and place it in the oven at 175 for an hour or so until it’s completely dry. Toss with a few drops of your favorite essential oils to additionally help ensure that the mice won’t come snacking. Fun times

  21. Lauren December 16, 2017 at 3:53 am - Reply

    I just got fabric to make these. I bought flannel not Cotton. Is there a specific reason why cotton is used over flannel? I got the flannel because it is so much softer. Is it essential to make it with cotton and then make a cover for it? Thanks!

    • Julie December 16, 2017 at 5:47 am - Reply

      Flannel is typically made of cotton. Cotton is the fiber and doesn’t describe the type of fabric. For example, denim is typical woven from cotton as is flannel which t-shirts are often knit from cotton as are some socks and underwear. Hope this helps!

  22. Lauren December 16, 2017 at 5:25 pm - Reply

    Thank You for your quick response!! I feel confident now that flannel will work fine. I’m so excited to make these as Christmas gifts.

  23. Becky December 18, 2017 at 4:04 am - Reply

    If you use the feed corn, you can store it in the freezer and you will not have to use it all right away.

  24. Jill December 18, 2017 at 11:37 am - Reply

    I have a question. I used whole corn. Said it was for cattle sheep and goats.
    And I made my cover with fleese. When I microwave it, it comes out wet.
    Do you have any idea if it’s the wrong corn? Or the fleece? Or a combination of the two? Unfortunately I made a bunch of them for Christmas presents. I could use help so that I can finish them. Thank you so much for all your work on researching!

    • CrispyKristin December 18, 2017 at 3:48 pm - Reply

      I’m not sure why it would be wet, but fleece is not usually 100% cotton so I wouldn’t use that as a cover. I wonder if the corn can’t breathe or the fleece is melting in the microwave?

  25. Darla A Drotar December 18, 2017 at 5:17 pm - Reply

    Thanks for all the great information, I love the comfort of a warm pack on a cold night but hated the smell of the old bed buddies. I will be making my own with flannel and jasmine rice today.

  26. Amanda December 23, 2017 at 8:03 pm - Reply

    It is interesting to see the different filling options. I use whole oats that I get at the feed store. I find that though dusty they do work well. I don’t bother to rinse them first. It smells kind of like bread when heated. I haven’t had much trouble with bugs using this and it is really cheap. The bags are damp for the first several heatings until the excess moisture in the oats is gone. I have never used a cup of water in the microwave with mine and haven’t had any issues to date.

  27. Mars December 26, 2017 at 2:32 am - Reply

    Wow. So much great info from all of u. Thanks so much. I have not made mine yet. Still researching. Now that I found this site I think I can begin. Will keep u up to date on my progress. Thanks SOOO much.
    Mars in Pa.

  28. Dawn Green December 27, 2017 at 12:44 pm - Reply

    I also use oats from the feed store. I ask for triple washed oats that they feed the horses so there is no dust. Nice heat and retains heat for awhile.
    I use flannel and have had no problems heating in the microwave without water.

  29. Deborah December 27, 2017 at 8:00 pm - Reply

    Have you ever tried hemp seeds? I have come into a large amount of hemp seeds and am.wondering if I could make hot packs with them?

    Thanks.

  30. BSnyder December 28, 2017 at 3:30 pm - Reply

    Flax seeds do make wonderful cold packs! 🙂 I made them years ago because my daughter is allergic to rice. I happened to have whole flax seed on hand and so used it. It was a happy surprise. She has autism and so is sensory sensitive. These feel great too.

  31. diane December 29, 2017 at 8:41 pm - Reply

    What about sand or small rocks as alternative to rice etc.

    • Kelli December 31, 2017 at 3:50 am - Reply

      SAND! What a great idea!!!

    • Jay January 5, 2018 at 12:51 am - Reply

      I read that sand is risky because it heats fast and gets very hot. Also it would be really difficult to keep inside of most stitched materials even with really small seams. I’ve never tried it though.

    • Megan Perkins February 24, 2018 at 6:25 am - Reply

      Not for the microwave! If there’s even a little bit of a metallic mineral in the sand, you may destroy the microwave. Says the one who left a spoon in mug of tea while heating it up… Also the glassy particles may shatter further. Think about non-pyrex glass.

  32. diane December 29, 2017 at 8:41 pm - Reply

    would glass beads work

  33. Maureen December 31, 2017 at 1:58 am - Reply

    Thank you so much for all the time you put into researching the fillings. This is so helpful.
    Do you know where I can get herbs such as white willow, lemongrass, valerian etc….wholesale?

  34. Lauren December 31, 2017 at 2:28 am - Reply

    Another grateful commenter here! I simply searched for a comparison of rice vs buckwheat for hot pack filling; I didn’t imagine finding such a well-written comparison! Your effort is very much appreciated as, given the miserable weather we’re having lately, I’m ready to make about a billion of these to stuff into mittens, slippers, pillows, etc…. 😀

  35. Sapphire iiis January 2, 2018 at 1:49 am - Reply

    I’v made several heat packs using whole Flaxseed and found them to keep the heat sufficiently, I much prefer the smell of heated flax compared to wheat and if there is wheat shellings it pokes through the fabric. The flax has never gone rancid even after years of use. Jasmine rice seems like a good option once I use up all my flaxseed. Thanks for the review. Very helpful!

  36. Joyce January 6, 2018 at 12:54 pm - Reply

    Has anyone tried pea gravel as a filler? I saw it suggested on a different site, and wondered about it. Don’t know if it might be harmful to the microwave or not?

  37. Joyce January 6, 2018 at 12:56 pm - Reply

    Thank you so much for all your time and effort for the research and good information!

  38. Ruth Block January 9, 2018 at 4:00 am - Reply

    I spritz the pack in the micro before heating. Any other comments on that?
    And I’ve used the demim from the both of cut-off jeans – after they split off at the knees. Re-purposing?
    Thanks so much! Ruth

  39. J January 12, 2018 at 5:53 am - Reply

    Yes, thank you for all your research. The current bags I got as a gift years ago are lavendar seeds. At least that was what I was told. I havent opened up the bag to confirm. Do you know anything about using lavendar seeds? It smelled wonderful until I over microwaved it, and it started to burn.
    Thank you

  40. J January 12, 2018 at 5:58 am - Reply

    I take that last comment backabout it smelling burnt. I forgot that I washed it several times – it smells like lavendar again. Its probably 25 years old, so it would be safe to assume that it is lavendar seeds.

    Thanks again.

  41. J January 12, 2018 at 5:59 am - Reply

    Hello,

    I take that last comment backabout it smelling burnt. I forgot that I washed it several times – it smells like lavendar again. Its probably 25 years old, so it would be safe to assume that it is lavendar seeds.

    Thanks again.

  42. Amanda Drew January 18, 2018 at 8:53 pm - Reply

    I’m glad that you figured out that jasmine rice, walnut shells, and whole corn are the best options to fill a comfort pack. Recently, I’ve been wanting to get one because my jaw has been hurting, and I think it would be very nice to put heat on it. I’ll have to find a comfort pack that has one of those options in it to buy.

  43. Joanna Hinton January 19, 2018 at 10:50 pm - Reply

    Hi. I just made my first shoulder wrap for my husband as he burned up his corn/filled one in microwave he’s been using for years. Neither of us knew you should microwave with a cup of water when heating it or spritzing with water; that sure makes sense now. For my wrap I used Long grain rice. I may have overfilled the wrap because it is quite heavy. I’m wondering now about a mixture of feed corn and rice; 50:50? Has Anyone tried that? I also added drops of essential oil in rice, stirred/mixed well before filling. Smells great upon heating.Thank you for sharing your research.

  44. Laura January 28, 2018 at 1:21 pm - Reply

    Thank you very much for all the great info! I really appreciate that you took the time to post.

  45. CHRISTY ROBINSON January 30, 2018 at 12:38 am - Reply

    How did each grain do? Specifically, how did pot barely do? I bought something made from pot barley but scent didn’t last long. Thanks for heads up on the need to refragrance it after time. I don’t want the food smell to over power the fragrance so I’m looking for something to replace the barley. I also forgot about the cup of water during heating so that could also have ruined the scent. Is dried lavender safw to microwave?

    • Megan Perkins February 24, 2018 at 6:29 am - Reply

      I throw a handful or two of dried lavender in with the rice in mine and it’s great. In older heat pads, it’s deteriorated to dust after a year or longer.

  46. Lynn February 6, 2018 at 1:33 am - Reply

    Thanks so much for the research…exactly the info I needed to make my heating pads, You provided the answers to all the questions I had before I started this project.

  47. Kimberly Rosetta February 8, 2018 at 2:07 am - Reply

    Thanks for the info! I have a question though. Of all of the fillers, which seemed to feel heavier than the others?

  48. Paulus Jordanicus February 19, 2018 at 7:01 pm - Reply

    My daughter whipped one up for me about 10 years ago. Used plain white rice… not jasmine or other fancy stuff. Still going strong. No smells. Heats up in 30 seconds or less. Retains heat for quite some time. Rarely have I ever had to reheat it to sock away the pains, generally in my shoulder.

  49. Annette March 5, 2018 at 11:29 pm - Reply

    Thanks!

  50. karen March 24, 2018 at 4:12 pm - Reply

    such a thoughtful resource – thank you for taking the time! You saved me time and money! And, provided some enjoyment along the way….I’ve taken the Jasmine rice and added some lavender….Yum and AHHHHHHH…

  51. Betty Lou March 29, 2018 at 1:53 pm - Reply

    I have always used whole oats can I use combination of Jasmine rice with oats .

    • CrispyKristin March 30, 2018 at 11:48 pm - Reply

      Yes, you can combine any of the fillings in any proportions you’d like!

  52. Sandy April 1, 2018 at 1:53 am - Reply

    Excellent post!
    Thank you

  53. Susan April 2, 2018 at 2:26 am - Reply

    Anyone try bird seed??

  54. M moon April 5, 2018 at 5:27 am - Reply

    I do not have a microwave and spent years missing my heating pack. I found the solution salt. I heat it up in a pot outside of the pack then pour it back into the fabric bag/pack. Works awesome. stays hot along time. Can get too hot and burn you or the fabric. So I often use it inside a pillow case.

  55. K. Mary April 9, 2018 at 3:02 pm - Reply

    Thanks so much for your research and results. Thank you, too, for all the comments and ideas. I’m ready to make my own ….

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