June Can Jam: Slow Cooker Blueberry Butter

washing blueberries

Well kids. The Tigress Can Jam challenge this month was anything that ended in “erries” and since this is my summer of fruit butters, I have made a batch of blueberry butter. Last weekend, my friend Shay and I took a little drive out to my favorite blueberry pickin’ spot in South Jersey and spent a couple of hours rattling berries from branches, filling our buckets and bellies.

However, the true treat of the day came when we rounded the corner of the farm stand in order to pay for our hauls. Standing right in front was my cousin Amy, out for a day of picking with her partner and two of their grandkids. We had one of those truly lovely moments, when you gape open-mouthed for a moment before laughing and falling into hugs.

blueberries in the Vitamix

Once home with my seven and a half pounds of berries, I spent several days eating them popcorn-style out of bowls, before hunkering down and making a preservation plan for the rest. Last year I called blueberry my foundational jam and that’s still a phrase that feels correct. I will always love that simple jam (in fact, I still have some from last year), but this time around I wanted to try something slightly different.

Originally I had planned to make a blueberry butter spiked with a hint of lavender, but this week was busy enough that I didn’t have a chance to get to Reading Terminal Market and that’s the only place close by where I can get food-grade lavender. So I went simple and stuck with my mom’s preferred flavor profile of lemon zest, cinnamon and just a bit of nutmeg.

drippy slow cooker

Lately, I’ve been turning to two gadgets to make my preserving work just a little bit easier to accomplish. The first is my trusty Vita-mix. I grew up with the vintage chrome version of this incredible blender and so during wedding time last year, made it a priority to dedicate some of our gifted resources to acquiring my own.

While I had an inkling that it had the potential to be a transformative piece of equipment, I had no idea how it would revolutionize my jam making. Here’s what makes it so special: When you run it on very low speed, it doesn’t puree the fruit. It just chops it up into small bits, which coincidentally, are the absolutely perfect size for jams and butters. I know it’s a little bit unfair to rave about something that’s so darned expensive, but really, this thing has changed my life for the better.

half pint of blueberry butter

The other small electrical appliance (that happens to be on the very other end of the cost spectrum) that I’m using all the time these days is my ancient, $3-at-a-thrift-store slow cooker. I’ve found that older slow cookers are far superior to newer ones, because they cook at lower temperatures. Truly, food safety regulations have made it so that what was once the high setting on the old pots is now the low setting on the new ones (you should never be able to achieve a boil in one of the pots from the seventies or eighties). And when you’re cooking a butter, you want to cook it as low and slow as you can. Slow cookers are truly perfect for this.

This particular butter reminds me a bit of blueberry pie, which makes it a winner in my book. Tomorrow morning, I’m having some friends over to do a little fruit butter tasting (in recent days, I’ve also made apricot butter and sweet cherry butter). We’ll see if they like the blueberry version as much as I do.

Slow Cooker Blueberry Butter

Yield: Approximately 3 1/2 Pints

Ingredients

  • 8 cups of pureed blueberries
  • 2 cups sugar
  • 1 lemon, zested
  • 2 teaspoons cinnamon
  • 1/2 teaspoon grated nutmeg

Instructions

  1. Put the pureed blueberries in a slow cooker. Place a lid on the pot and turn it on to low. After about an hour, give it a stir. At this point, you want to use something to prop the lid a bit. I found that laying a wooden spoon across the rim of the cooker and then placing the lid on gave it just enough room to let the steam evaporate.
  2. My blueberry butter spent about six hours in the slow cooker (from 5:30 p.m. when I got home from work, until 11:30 p.m. when I canned and processed it). At the beginning of hour five, I added the spices, lemon zest, and the sugar, removed the lid completely and turned the heat up to high, in order to speed the cooking down.
  3. Once it’s cooked down sufficiently*, pour into jars (leave a good 1/2 inch of head space), wipe rims, apply lids and screw on bands. Process in a boiling water canner for 10 minutes. Eat on fresh scones and store unopened jars in a cool, dark place.

Notes

*When the cooking process is done, you can puree with an immersion blender or (carefully) in a regular blender, for a smoother product. It depends on whether you like your butters a bit chunky or very smooth.

https://foodinjars.com/recipe/june-can-jam-slow-cooker-blueberry-butter/

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167 responses to “June Can Jam: Slow Cooker Blueberry Butter”

  1. So if you were to use lavender instead, do you have a suggestion for how much? And one would just add the dried blossoms straight in place of the spices?

  2. This may be very elementary, but why/how is it considered a butter? Also… What is the difference between a jam, jelly, butter, etc.
    Thanks!

  3. I recently made my first fruit butter. Plum. I had 11 pounds of Italin Plums in the freezer, the last of the 35 pounds my little tree produced last year. I figured that after being frozen for so long butter would be the best use. Now I heart fruit butter! Your blueberry recipe sounds wonderful. Blueberry Butter here I come.

  4. Huh. I had no idea you can make blueberry butter. I always make blueberry jam and I like it but I think I’d like the smooth texture of blueberry butter even more.

    Wondering if you can process the blueberries in a food processor in lieu of a Vitamix (which I am completely jealous of, BTW)

  5. Looks and sounds fantastic – I’m just trying to think out how to do this in a “new” slowcooker… maybe 1/2 the time? I hate to get a second slowcooker from the thrift store, just to get the super-low, super-slow cooking effect. (my kitchen is not that big!)

  6. I love your blueberry butter. I’ve been making apple butter in my crockpot for a few years now. For butters, it’s the only way to go in my opinion. Have not even thought to try blueberry butter. Thanks for the recipe.

  7. Marisa, what else can you make in the crock pot? I really like this idea, and have apricots, peaches and plums to can. Can I follow your basic recipe above with the different fruits, or do I need to adjust the ingredients. And, can I make slow cook, no-pectin jam in the crock pot? Would love to have a way to get the caramely flavor, without having to stand over a hot pot all afternoon!

  8. What amazing timing! Blueberries were on sale today and I bought a pound. Maybe I’ll try making a tiny batch of this. I have a newer model crock pot though… Would the low setting be low enough or should I put it on Warm for a few hours? I don’t have any lemons though, so I might either skip the lemon zest, or add a bit of my roommate’s homemade limoncello and hope the alcohol cooks off and doesn’t leave any flavor but the lemon peel.

  9. I am new to canning. I just bought my first pressure canner a few weeks ago. I think that this recipe will be my first experiment with using it (for hot water bath)! I can’t wait to try the blueberry butter!!

  10. Yes! This sounds fab. I love blueberries but I am not a fan of blueberry jam because it never gets firm enough for my taste. Blueberry butter sounds perfect. Thanks!

  11. last summer, I bought 8 pounds of blueberries, but they never made it to jam (strait into my kids bellies). They’re at camp this week and I just picked up 4 pints of blues- maybe they’ll make it into a jar this year!

  12. Jam in a slow-cooker is genius. Of course, now I imagine that my slow-cooker is too hot for this, which is a bit of a shame, but I’m really looking forward to trying this to see how it goes.

  13. I just tried this yesterday but with star anise as my spice of choice! I don’t think I cooked it down enough, but it was pretty tasty on some bread!

  14. Love this idea and recipe!! Could you please post the sweet cherry butter recipe? I have a ton of cherries that need to be used up and that sounds amazing!!

  15. I just made this yesterday, and it turned out soooo goood! I think I may have messed up somewhere because for me it made 3 1/2 half pints. But, like I said it turned out perfectly in my opinion. Thank you so much for the recipe!
    P.S. I put some on lemon biscotti, and might I say heaven.

  16. I have made apple butter in the slow cooker many times and found that my newer model worked fine using the high setting for about an hour with the remaining time on low setting. However, when I tried the blueberry butter, I used the warm setting. It worked great! The finished product was delicious.

    I had a few spoonfuls leftover that couldn’t fit in a jar, so I threw them in the ice cream maker with a basic vanilla recipe. My husband swore it was the best ice cream I’d ever made!

  17. I made this last night and I have to say, I messed it up. I didn’t chop up the berries (I didn’t want to wash out my processor) and then I forgot to take the lid off for 4 hours — so it really turned out more like blueberry sauce (I even put it through a food mill because those berries just were NOT breaking down like I thought they would). I didn’t have cinnamon, but I put it 2 T of lemon juice and the zest of one orange (plus the cinnamon) and it has yummy holiday flavors. I just called it blueberry sauce, and I think it will be great on pancakes, etc., but I still really want a blueberry butter! Oh well. I’ll try again in a few weeks.
    ~Marisa, I also made your rhubarb-rosemary jam yesterday. OH MY GOODNESS. I can’t stop eating it! So yummy.~

  18. This recipe looks totally fab. I can never resist a vintage slow cooker on sale for a song in a charity shop, so have a few. Am really looking forward to giving this recipe a go. Unfortunately blueberries are still sold in tiny little punnets in the UK and cost a fortune. Eventually I will grow enough to make jams with. Thanks for the inspiration.

  19. I am excited to make this and am even going picking this weekend just for this recipe. But I need to know if I can make it in my newer slow cooker. Any ideas out there?

  20. Kate, I’m working on a post with more details about making fruit butters in a crock pot. I did want to drop and respond to say that you can use a newer crock pot to make fruit butters, you just have to watch it more and keep it on low the entire time.

  21. Well, after reading your recipe and everyone’s comments I know what I’m doing tomorrow (and taking to our friends annual 4th of July barbque)…I just need to go get some more fresh blueberries as they are ripe and plentiful. Thank you for sharing!

  22. Quick question..when you say “8 cups pureed blueberries”..is that 8 cups of berries, or 8 cups of puree? Thanks.

  23. I know it’s probably been said already, but I LOVE the slow cooker idea. I am so on that. I have an awesome 70’s one with a brick motif that I use for hot spiced cider in the fall. Now it’s going to work in the summer! Thanks, Marisa!

  24. Emily Rae, you sound like my kind of cook! My sister laughs at me because she is the more careful cook of the family, but sometimes my flights of fancy work out!

  25. I am going to make this! Soooo good! I have 3 blueberry bushes planted two years ago. Prducing well but can’t wait for what they’ll provide in the next two years or so!

  26. I am slapping my forehead over the Vita-mix tip. We got one not too long ago, but so far it’s been my partner’s domain. Now I see how I can use it for my jams. I think you’ve just changed my life for the better, too. I’m looking forward to trying slow-cooker butter as well.

  27. I’m interested in your apricot butter. I have apricots coming out my ears and can only make so much jam. Please post?

  28. It sounds wonderful. I just went to a peach farm today and bought 1 1/2 bushel of SC peaches. I had also stopped at the farmer’s market and bought fresh blueberries. (I had already picked 13 lb. but they are in the freezer.)
    Do you think I could make peach, blueberry butter? Thanks for any help you can give me. I hope I am doing this right, my first time.

    • Ginny, I’ve made peach butter in the slow cooker to great success. I’ve never done a fruit combination like that before using this technique, but I imagine it would work. The only thing to note is that the blueberries will be the dominate color in the finished butter.

  29. Marisa, I will think about combining the fruits, maybe I should just make a peach and then a blueberry.
    I am so pleased I found your page.
    Thanks again,
    Ginny

  30. I just found this website and love it! I am trying to do some canning this year and live near Philadelphia. Marisa – where do you get your fruit or at least the blueberries? Sweetest I have found are near Hammonton but I do not have the time to go there this year before the season ends!

  31. I made my first fruit butter (cherry) a few weeks ago, and love it, so I am making blueberry butter today! Does the lemon do anything to help preserve the butter, or is it added merely for taste? And did you use the whole lemon or just the zest?

  32. I doubled the recipe to fit our big crock pot (I think it’s 6 or 7 quart). I ended up with 15 half-pints of fantastic blueberry butter! With our newer model, I kept the temps between the “keep warm” and “low” settings. My children absolutely love it in their oatmeal and hot cereal as well as on waffles, pancakes, biscuits, etc.! Thank you for the recipe.

  33. Thanks for all of your inspirational posts! I just started canning this year and I tried your recipe for slow cooker blueberry butter. I had to halve the recipe and I think I may have added extra lime zest because the lime is pronounced in mine. Still I liked it a lot. While waiting for the results from the slow cooker, I made strawberry ice cream.

  34. I have to thank you for this recipe, it is now one of my favorite treats in the morning. I changed it a little by using Splenda 1/2 instead of sugar the results worked out good. lucky we keep that old crock pot we got as a wedding gift, I can see a future for it again. I heard about your site off of Gardenfork Radio and since I had canned most my young life, but just got back into it, I thought I would check out your site for some tips and inspiration, and I am sure glad I did. Thank You for your hard work and I hope I can return the favor one day.
    Joey

  35. Done! Using the slow cooker was a great idea, considering we have had some too hot to turn the stove on type days. My 8 cups whole blueberries (then pureed down to something less…) made 4 cups lemony blue-butter, and yes, its delish!
    The wine jelly i had in mind to get to this weekend may have to wait, since the August CanJam tomatoe butter sounds more intriguing than ketchup.
    Thanks for the brilliant idea of putting the slow cooker to another good use.
    I make a beautiful deep port coloured Italian Prune Plum butter with Chinese 5 Spice and this has been on almost every meat, bread and dairy product we have eaten this past year! Give that a try when your local plums are ready.

  36. […] Slow Cooker Blueberry Butter | Food in Jars I like to do a lot of small jars of different jams, condiments, etc. for holiday gifts. Last year I made apple butter, but I think would be a nice change and now is the time to make use of the billions of blueberries at the farmer’s market. (tags: gifts canning recipes) […]

  37. Would this work with sour cherries? I expect I may have to adjust the sugar to make sure it’s sweet enough, but are there other adjustments you’d suggest? Thank you so much for blogging about preserving!

  38. Hello,
    I am making the blueberry butter right now. I find that it doesn’t look really blue or purple. It tastes good it looks more like chocolate. I have stirred it quite frequently so it doesn’t burn. And it has taken about 8 hours on low and still needs a bit more time. Let me know if I am doing this right.
    Thanks for all the advice!
    Kelly

  39. Do you have the recipe for sweet cherry butter posted somewhere? I’d love to have it- I’m making fruit butters as favors for my wedding, starting with this blueberry one today!

  40. a little cardamon does well too! I’m thinking this year’s batch with a spice trio cinnamon, cardamon and crystallized ginger. A friend of mine has a 5 year old nephew, who called her at 11 p.m. to tell her “I need some more of that black jelly cause it’s the best I ever had in my whole life” 🙂

  41. perfect timing on the advice of using an older model slow cooker, I have one I was considering throwing out ’cause the lid is cracked, sound like it is perfect for fruit butter making.

    • A local Goodwill store is a great place to find an odd lid – I found an extra for my 3-quart Crock Pot (I bought the very first Crock Pot on the market back in the ’70s & it’s never been allowed to rest).

  42. I’m going to make this today. Headed out to get the berrys now. Just need to make sure about the amount. Does this make 3 half pints or 3 and 1/2 , pint jars? Thank-you. Jeanette

    • It makes three and a half pints of blueberry butter. Remember that yield can vary depending on the amount of water in the fruit, so know that your results may not be identical to mine.

  43. i made this yesterday. while it is indeed yummy, it did not firm up like a “butter”. how thick should it be getting in the slow cooker? i cooked it for at least another hour with the top off, stirring frequently to get the water to cook off. i ended up with 3 good-szd pint jars-full, but it was much more fluid than i would have thought.

    does it have something to do with the age of the slowcooker? i see lots of posts about the older cookers. mine is newer, and large and oval-shaped. does that make a difference?

    also, i would use less lemon zest. an entire lemon’s worth is a bit much, i think.

    i would really appreciate some more info, as i liked this way of using all the blueberries on our bushes. i got all 8 cups from my own backyard.

    thanks!

    • Evi, every slow cooker is a little bit different and every batch is a bit different. The cooking time can vary a great deal depending on the amount of water in the fruit you’re using, the humidity in the air and the size and shape of your cooker. However, this is the beauty of making it yourself. You can cook it to your own specifications. If you want it to be thicker, you cook it longer. If you don’t like as much lemon zest, you simply use it less. You don’t have to follow my recipe to the T. I made it the way I like it. You should do the same.

      • thanks marissa – i’m not a super-inventive cook, especially with a process like canning and preserving, to which i am quite new. i like to try a recipe as it’s written first and then see if/how i might change it. just wanted some ideas on what the preferred viscosity would be at the end. should it be like whipped honey? like soft butter? like jam?

  44. Can I use frozen berries? If so, would I need to let them thaw first or could I throw them in my Vitamix right from the freezer? I have been making yogurt in my slow cooker and I think this blueberry butter might just be the perfect topping, but it’s winter here in MN and the fresh blueberries are not much to be desired. Thanks!

    • I’ve not made this butter with frozen berries, so I can’t tell you how it will turn out. I will recommend that you let the berries at least partially thaw before you put them in the Vitamix, just so it’s a little easier on the machine.

      • I just made the blueberry butter (from the book) and I used frozen blueberries. I think that was a mistake because the yield was much smaller. At the end it only made less than 4 half-pint jars. I will cook down some more blueberries tomorrow and add it to the rest of the batch. That would explain though why the cinnamon and lemon taste is so strong.

  45. I love the idea of blueberries and the slow cooker. However, preserving/canning has never been anything I was willing to try. Small NY apartment, space being one issue. Is this something I could freeze in small portions?

  46. Thanks for the tips on the older slow cooker especially. We make jam every fall with cloudberries we pick up here in Alaska. I think this will help us out.
    Greetings from north of the Arctic Circle.

  47. Just finished canning this! The only adaptations I made were eyeballing a out a tablespoon of pumpkin pie spice instead of cinnamon and squeezed in the juice from the lemon! Yummy recipe! Will make it again next summer!

  48. I just made this tonight. SO EASY and so yummy! Next time I’m going to experiment a little more, but this recipe is incredible as is. Thank you for helping me find a use for more of my blueberries – I bought 15lbs! 🙂

    • also – I stopped by on my way home and got an older model slow cooker as you suggested. It was 5 bucks at a local thrift store and I tell you what, worked like a charm. Thanks again!

  49. Fantastic recipe. Very simple but delicious! Yummy warm Berry cobbler… in a jar! Thank you for sharing

  50. I just made some of this blueberry butter, and I love it. I think I like it better than blueberry jam, because it’s not as sweet.

    Cooking Light has a great Slow Cooker Apple Butter recipe on their website that you leave going all night. The house smells magnificent in the morning.

    I particularly like that they have you leave the skins on and cores in, and then pass it it through a sieve when its soft. Saves a lot of work, especially the one time I made crabapple sauce!

  51. As I do not have a boiling water canner but do have a Dutch oven: Is it OK – or possible – to put the jelly jars in the Dutch oven? If so, do the jars go right on the bottom of the pot or do they need a rack? Should the jars be touching each other – touching sides of the pot? How much water should be in the pot? An inch over the top of the sealed jars? After they are processed, should I handle them as I do for tomatoes processed in the pressure cooker – remove to clean folded towel to cool & seal collapses & screw band is tightened after contents cools a little? Can the jars be frozen? (it would not be possible to find a cool spot in the house, unless 75 degrees is considered cool) I would love to give these as Christmas gifts, as well as have some for myself. Many thanks for your help.

  52. Can you can these? i made some pineapple butter and now i have about 10 jars and im wondering what to do with it can it, freeze it or what?

    • There are canning recipes written into the recipe, so yes, you can can this one. I’ve never made pineapple butter, so I don’t know if it can be canned.

  53. Wow sorry if that sounded snakry lol didn’t relise that till i re-read it after i posted :/ im new to canning and not sure if you need some special preservative to make sure it safe.

  54. I’ve a bunch of Saskatoon berries that I picked this Summer.. at the time, I’d never canned a thing in my life, or thought that I would! ..fast forward 2 months later, and its a whole other story.

    This sounds like a fantastic way to use some of those berries, though I’m wondering if I should just wait until next summer, or if my frozen ones would be okay?

    If you’re not familiar, Saskatoons are similar to Blueberries. 🙂

  55. Great recipe! I just happen to have an old (smaller) slo cooker, perfect for this.
    I’m always confused on the conflicting advice on how much space to leave at top of jar. Some recipes say fill it right up, as this STOPS any mould getting in, others the exact opposite! Which one is it? It can’t be both! Thanks.

  56. I hope some ones on here soon. LOL I made this 2 yrs ago and loved it. I just pureed my berrys and put in the C.P. They have been in there an hour. I stirred them and it is REALLY thick. I cant remember if that’s normal? its almost like jam now. will it cook down to get some liquid in it or did I puree to much? Please help I love this recipe. Thank-you.

  57. You have pretty much come to my rescue with this recipe, as I have 20 lbs. of blueberries and a double crock pot that is begging to be put to a good use. I may try adding a little vanilla bean (and maybe some lemon verbena!) to the mix and see how that goes too. Thank you sooooo much!!!

  58. My butter didn’t set into butter. It’s more like a jam. Followed directions exactly and after 6 hrs when it hadn’t set I moved it to the stove and simmered for another 40 minutes. Any ideas on what to do to help it set? Or should the consistency just be like a jam? I kind of pictured it being super thick like apple or pumpkin butter.

    Any suggestions would be appreciated as I was going to do another batch w/vanilla bean in it! Thanks so much.

    • Tami, cooking times vary for products like this. Just because mine took six hours doesn’t mean that yours will be done in exactly that much time. Thought it’s been awhile since I made this butter, I seem to recall that it doesn’t get quite as thick as apple or pumpkin butters do.

      • Wow – thanks for the quick reply, Marisa! And for helping me get a better understanding of the expected consistency. I made it last night and can’t wait to taste it. Just picked up your book and love it 🙂

  59. I love the blueberry butter recipe, i realized i dont have the lemon on hand as i started this project, arrgh, but i think i will just improvise with this trial batch and use orange zest and juice, i love the combination of oranges and blueberries. wish me luck!

  60. Hi! I found your slow cooker blueberry butter because I was looking for slow cooker raspberry butter. Do you know if this can be done? Do I have to use lemon or pectin? Can’t I just cook it down using only my raspberries and a little water and then process it in a boiling water bath?

    I look forward to hearing from you.

  61. Marisa – do you think I could do this recipe with saskatoon berries? I don’t see any saskatoon berry recipes on your site but thought you’d probably know if I should adjust anything… Add some lemon juice maybe?

    • I have never used saskatoon berries, so I really don’t know. However, according to this article, they have a low enough pH that they can safely be canned in a boiling water bath. So I would give it a shot!

  62. This is my first time canning so I don’t know if I am really doing everything correctly. I had to cook my Blueberries on the stove. Now, after I put the sugar and spices in, let it cook for an hour is was still gritty. Is it supposed to be like this?

    • It should not be gritty and I’m not exactly sure why it is. Did you puree it really well with an immersion blender? Did the sugar fully dissolve? Were the blueberries totally clean?

  63. I have that same slow cooker. LOL. I appreciate your thoughts on old vs. new. I can’t wait to try this recipe now.

  64. This blueberry butter was fantastic and a nice substitute for blueberry jam. I decided to make blueberry ice cream using the blueberry butter and turned out amazing! Possibly the best flavored ice cream I’ve ever had. Only used 1 1/2 pints of the butter for a 10 yolk, 3 c. milk, 3 c. cream recipe and it added intense flavor. I did add another 2 c. of sugar to the ice cream recipe in addition to what went into the butter but it wasn’t too sweet, just right. A must try!

  65. Just canned this using 1/2 inch head space as recommended in the recipe. I was sure this would win at the county fair. Unfortunately I checked the local fairs guide lines after canning and they require 1/4 inch head space.

  66. Hi Marisa,

    I just made a batch of your heavenly blueberry butter recipe from your Food in Jars book. I’ve received many compliments about it and would like to make a bunch of jars for Christmas gifts but noticed the recipe recommends keeping it stored up to six months. Is there any wiggle room with this timeline?

    Many thanks,
    Jennifer

    • Hi Again – I just found the answer to my question on another Food in Jars web page. Thanks for all the good information you provide to us canners.

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