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


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


  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.


*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.


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167 Responses to June Can Jam: Slow Cooker Blueberry Butter

  1. 1
    melissa says:

    ooh, I would not have thought of blueberry butter. must try!

  2. 2

    I love it! As soon as I get some Lac St Jean blueberries in, I am so making this! You just made my day, and the restaurant is gonna love it! Thank you so much!

  3. 3
    Kate says:

    I am sold on slow cooker butter; thanks for the inspiration and great post!

  4. 4
    Erin says:

    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?

  5. 5
    Annie says:

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

  6. 6
    Terri says:

    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.

  7. 7
    meg says:

    This looks fantastic! I haven’t made a fruit butter yet, but hope to this summer. Slow cooker- great idea!

  8. 8
    Jennifer says:

    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)

  9. 9
    Rachel says:

    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!)

  10. 10
    Bonnie says:

    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.

  11. 11
    Cindy says:

    What a great idea! I never thought of using the crockpot for making butters.

  12. 12
    Gudrun says:

    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!

  13. 13
    Aba says:

    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.

  14. 14
    tigress says:

    i am always on the look-out for blueberry recipes. i love the idea of a butter. good one! and that top photo – amazing!

  15. 15
    Emily says:

    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!!

  16. 16
    Kristen says:

    That looks SO good. I only wish I lived where I could get my hands on a bunch of blueberries cheap.

  17. 17
    Brenna Fisk says:

    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!

  18. 18
    momchelle says:

    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!

  19. 19
    Jenn says:

    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.

  20. 20
    maya-marie says:

    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!

  21. 21

    I Love the idea of jam in the slow cooker. Blueberries are in down here in Florida. I have this recipe in my slow cooker as I type. Can’t wait to taste it later tonight. Yummmmm

  22. 22

    Had no idea you could make that in a slow cooker! How wonderful. I have an abundance of blueberries and have just discovered how much I like canning. Thanks for the recipe.

  23. 23
    Juliw says:

    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!!

  24. 24
    Jase says:

    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.

  25. 25
    Sarah says:

    That’s a really good tidbit about older slow cookers!

  26. 26
    Torie says:

    Thank you for the great recipe!

  27. 27
    Kelly says:

    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!

  28. 28
    Emily Rae says:

    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.~

  29. 29
    Gloria says:

    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.

  30. 30
    Kate says:

    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?

  31. 31
    Marisa says:

    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.

  32. 32
    Central Valley Farm Gal says:

    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!

  33. 33

    […] knows, blueberries are pretty much the only option for the blue. This recipe from Food in Jars for Blueberry Butter uses a slow cooker to get the job done. How brilliant! You can be on grill duty while the blueberry […]

  34. 34
    NewToCanning says:

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

  35. 35

    […] Food in Jars put up some (Slow Cooker) Blueberry Butter.  It not only looks amazing, but using the slow cooker? Genius!   I want to try this and experiment with the method for strawberry or cherry butter.  […]

  36. 36
    Julia says:

    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!

  37. 37
    Kay S. says:

    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!

  38. 38

    […] were so many questions about cooking fruit butters in slow cookers left on the blueberry butter post that I thought I’d talk a little more about how it works, how to do it and why it’s a […]

  39. 39
    Paige says:

    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!

  40. 40
    Shae says:

    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.

  41. 41

    […] to cherry butter or apple butter – a preserve with no butter pats involved.) Here’s a Slow Cooker Blueberry Butter […]

  42. 42
    Tammy B. says:

    I’ll have to try this. I’ve done pear & apple butter b4 in a crockpot–I’m lazy. : )

  43. 43
    Faye says:

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

  44. 44
    Ginny says:

    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.

    • 44.1
      Marisa says:

      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.

  45. 45
    Ginny says:

    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,

  46. 46
    Ginny says:

    Marisa, I took a chance and made the blueberry, peach butter. It was delicious. Thanks for your help.

  47. 47
    Marisa says:

    Ginny, I’m so glad to hear that the combo worked so well! Hooray!

  48. 48
    Leigh says:

    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!

  49. 49

    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?

  50. 50
    Heather says:

    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.


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