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.
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.
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.
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
Ingredients
- 8 cups pureed blueberries
- 2 cups sugar
- 1 lemon zested
- 2 teaspoons cinnamon
- 1/2 teaspoon grated nutmeg
Instructions
- 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.
- 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.
- Once it’s cooked down sufficiently*, pour into jars (leave 1/2 inch of head space), wipe rims, apply lids and screw on bands. Process in a boiling water canner for 10 minutes.
- When the time is up, remove the lid from the pot and turn off the heat. Let the jars rest in the cooling water for five minutes. When that time is up, remove jars and set them on a folded kitchen towel to cool.
- When the jars have cooled enough that you can comfortably handle them, check the seals. Sealed jars can be stored at room temperature for up to a year. Any unsealed jars should be refrigerated and used promptly.
Hi Marisa! I started this recipe using your website but I also have my cookbook opened. I’ve really cooked this butter a lot longer than you call for as the website calls for 3 half pints, but now I’m looking at your book which states a yield of 3 pints. Wondering if I overcooked my butter?
It has been so long since I’ve made this recipe that I really can’t advise you too much. Typically my book recipes are the final draft versions, while the ones on the blog are sort of beginning drafts. The thing with fruit butters is that they are never super exact because sometimes the fruit has more water and sometimes it has less water and so the amount of time you need to cook it to get it to the right consistency just varies. So I would say that if it was still really runny, you probably didn’t overcook it, and that this is one where you have to embrace the uncertainty of it.
I made the blueberry butter again this year but it’s runny doesn’t seem to be settling at all what can I do
lindalarue@xplornet.ca
So sorry your blueberry butter isn’t working this year. It could have been a particularly wet year for blueberries.
How do you puree blueberries? I just put them in a blender until liquid?
Yes!
How long will this last in a pantry?
If properly canned, it will keep at least a year while still sealed.
I want to make this today, and from what I am reading, we are to use the ZEST only from the lemon and not the juice? Please can someone clarify for this newby to this Blueberry Butter.
Thank you.
R
It appears that when I first wrote this recipe, I only used the zest. However, you could also use the juice if you prefer.
Thank you for this recipe! Do you have an idea of what the slow cooker temp would be if entering manually? I’ve heard that low on a slow cooker is 195F, but suspect this is the modern number that you referred to.
I really don’t know what the exact temp might be. Perhaps something between 180-190F?
You are an inspiration and have gotten me interested in canning in a way I never expected! I have cross-referenced a few of your butter recipes and think I’ve figured this out, but is the lemon zest necessary for acidity (I don’t even know if the zest technically has acidic properties like juice does)? I’d love to make a batch but would prefer to omit the lemon, if it’s safe. Thank you for helping with my newbie questions!
The lemon is just there to balance the flavor. It’s not necessary for safety. You are welcome to omit it.
I made pear butter few years ago, and if you want a treat have pear butter with almond butter on your Belgium waffle. So good! I am excited to make blueberry butter. So thank you for this post and idea. I have enjoyed reading thru the comments. Keep creating! 🙂
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.
I’ve never canned before and am still too afraid to try. Once cooled, can I put this in freezer bags and freeze?
Freezer bags aren’t really a great vessel for jam. They’d do better in a small freezer-safe containers.
When do you add the lemon zest?
With the spices.
I scrolled awhile and didn’t see this question:
Are the blueberries measured before pureeing or after?
The recipe calls for 8 cups of pureed blueberries. So yes, they are pureed before measuring.
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.
Guidelines vary!
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!
I have that same slow cooker. LOL. I appreciate your thoughts on old vs. new. I can’t wait to try this recipe now.
Is the final product supposed to be gritty?
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?
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?
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!
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.
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!
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 🙂
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!!!
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.
UPDATE it is fine now another hour to go!
How much/how many half pint jars does this make?
If it makes 3 1/2 pints, you multiply by two to get the half pint yield (seven half pints).
Thanks for clarifying–I wasn’t sure if that was 3.5 pints or 3 half-pint jars. 🙂
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.
Jars won’t seal if you don’t leave some headspace. And if you’re processing your jars in a boiling water bath, you kill off any mold spores, so they are not an issue.
That’s that then! Thank you.
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. 🙂
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.
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.
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.
What is the nutritional information (calories, fat, carbohydrates)? Thanks
Sarah, I don’t have the resources to calculate that sort of thing.
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!
Fantastic recipe. Very simple but delicious! Yummy warm Berry cobbler… in a jar! Thank you for sharing
blueberry jam, tomorrow afternoon!
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!
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!
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.
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?
Yep!
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.
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?
It should have the consistency of blueberry pie filling.
Hi there,
This looks great. How many cups of whole blueberries yield 8 cups of pureed blueberries?
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.
Thanks for your quick reply. I cant wait for this to be done! I think I will use orange zest instead of lemon.
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).
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” 🙂
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!
I made this last summer and it was fabulous! I would highly recommend this recipe! We just used up our last jar!
This looks incredibly tasty. If only I lived a bit closer to a blueberry field.
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
Is it called butter when cooking slowly in crock pot? New at this, just trying to learn….have blueberries in slow cooking crock pot now, as typing.