Blueberry Jam Recipe
Its the beginning of summer, and that means blueberry season has started! Here is a relatively quick, easy blueberry jam recipe that’s intended as a freezer jam, and by that I mean jam you don’t have to can, but which is cooked. While most refrigerator jams are uncooked, some are, including this recipe. Cooking the jam helps it last longer, and personally, I feel it helps the flavors combine better. And pressure cooking the jam brings it up above the temperature it needs to set, so it relies solely on the pectin naturally within the fruit, so no additional pectin is needed. (That also reduces the cost of making the jam.) This recipe makes enough jam that you can have some now, freeze a little, and not so much you have to mess with thermometers, sterilizing jars, and water baths. The jam comes out a deep, deep blue color, with a lovely fragrance, and its delicious!
Blueberry Shopping Tips: I wish I had some magical tip to tell you how to get cheap blueberries, other than growing your own blueberries, but unfortunately, its more a question of avoiding paying top dollar for them. Most of the blueberry consumption in the United States is met through domestic production, so supply and prices are very seasonal: start checking your supermarket circulars for sales from early June through August (it may vary depending on your location). You can also look for “pick your own” blueberry farms – there are concentrations of blueberry growers in Maine, New Jersey, Michigan, North Carolina, Georgia, Florida, Oregon and Washington. For Canadians, blueberries are grown in British Columbia, Nova Scotia, New Brunswick, Prince Edward Island, and Quebec. I’m a big fan generally of Costco, and we bought a large container (2 ½ pounds) there last week at a decent price, and they were well kept in a very cold, refrigerated produce room.
Blueberries are a relatively fragile, perishable crop, so how they’ve been handled during shipment and by your retailer, as well as how you handle them once purchased, will affect their longevity. If they are kept in a refrigerated area, that will preserve their quality and increase their longevity. If they are sitting out at room temperature in a produce section, they won’t last as long. We like to bring a cooler with us when buying perishables, so we can store meat, dairy goods, fruit like berries, etc. in the cooler to protect them from the heat of the car while running errands. The more sides of the berries you can examine (clear plastic containers make this really easy) the better. Turn the container over and look at the berries on all sides: any surface moisture, crushed berries, juice on the bottom, withered berries, and signs of mold mean you should put the package back and look for another. Don’t mistake the white powder that is often on blueberries for mold, this is epicuticular wax, a naturally occurring fruit yeast, and its actually beneficial – epicuticular wax decreases moisture loss in the blueberry. Look for a vivid blue color: if you see a lot of red tints, you can still use the berries for jam, but they are underripe, and may be far less sweet if eaten fresh. Refrigerate the berries as soon as you get home (don’t get them wet before storing them).
Using Frozen Blueberries for Jam. Yes, you absolutely can use frozen berries for your jam and preserves. If cost is an issue, and frozen blueberries are less expensive per pound than fresh, by all means use them, just be sure to purchase whole, unsweetened berries – those that have been sweetened or are in syrup will throw off the balance of sugar in your jam. I just checked my local supermarket, and the best deal I found there for blueberries was a 3 pound bag of frozen blueberries for $10.99 each, or $3.66 a pound. If I recall correctly, the fresh blueberries were slightly less per pound than that, but at other times of the year, the frozen berries might be a much more economical choice.
Preparing the Blueberries for Jam and Preserves: If you are using frozen blueberries, I recommend you defrost them before putting them in your food processor or blender. You could risk damaging your bowl or blowing out your motor with very hard, frozen berries. You can either move them from the freezer to the refrigerator the day before so they can defrost slowly, or leave the bag out on the counter for a short while until they soften. For fresh berries, don’t wash them until immediately before you use them. Remove any stems and leaves on the berries, and remove any berries that have gone soft, shrunk, are mushy, or leaking liquid. If you have a large container with berries of varying sizes, I separate them, reserving the large berries for “showpiece” desserts like berries and ice cream, or blueberry pie, and I try to use all the smaller berries for jam. They’ll be pureed anyway, most of the anthocyanin, which makes blueberries blue, is located in the skin of the blueberry, and since smaller berries have a higher proportion of skin, using smaller berries will put more of the blue pigment into your jam and preserves. I also add any berries with red patches on them to the pile to be made into jam, because they are underripe, and while that will make them less sweet for eating fresh, its not a problem at all for jam making. I then weigh out the berries for the requisite amount, and wash only the portion for immediate use, putting the rest back into the refrigerator.
LEMON AND LEMON ZEST TIP: You may be tempted to use a Meyer lemon instead of a conventional one in this recipe, but don’t do that. While its true that Meyer lemons have a milder tasting juice, they are also less acidic, and their zest has a less intensely lemon flavor. You also need the acid: citric acid helps the gel to set, and both lemons and oranges contain natural pectin, which also helps the jam set.
1 pound (450 grams) blueberries (fresh or frozen)
1 /2 to 1 lb. (225 to 450 grams) granulated sugar
1 washed lemon (including zest)
¼ teaspoon lemon extract
1 tbs. butter (optional, vegans can omit)
pinch of cinnamon (optional)
Electric Pressure Cooker
12″ Silicone Tipped Tongs
Fine mesh strainer or colander
Bowl to macerate fruit and sugar
Blender or food processor
Long handled rubber or silicone spatula
Lemon Zester, Microplane Grater or Potato PeelerWooden Reamer or Citrus Juicer
- If you are using frozen blueberries, thaw them first. You can thaw them out overnight in the refrigerator, or put them out on the counter for a few minutes. If you are using fresh berries, remove stems and any blueberries which have shriveled, softened, are leaking juice, are moldy, or have other damage. If you purchased over a pound of berries, I recommend you then sort them, saving larger berries for serving with ice cream or pie, and using smaller berries for this recipe. Blueberries with red patches or shoulders (see arrow above) are underripe, and should be added to the berries for making jam.
- Put any extra berries back in the refrigerator. Immediately before using the blueberries, use a fine mesh strainer or colander to gently wash or rinse the berries off. You can let the water drain for a few minutes, if you like, but don’t wait too long. Moisture degrades the berries quite rapidly.
- Place the blueberries in the bowl of your blender or food processor. This recipe makes very smooth jam, so if you want chunks of blueberries mixed in, more like preserves or marmalade, reserve some of the berries, and keep them whole until after the blueberries have been pressure cooked (Step 13).
- Pulse the blender or food processor a few times, remove the lid, and scrape down the sides of the bowl with a spatula.
- Continue pulsing the berries, every so often, stopping to scrape down the sides of the bowl so all the blueberry pieces are pureed.
- Once the blueberries have been pureed to a smooth consistency, remove the food processor blade from the bowl (you can gently tap it on the side of the bowl to knock back any puree into the bowl) and remove it from your work area. Using your spatula, scrape the puree out of the food processor and putting it in a bowl or other container. Do not be concerned that the mixture has turned reddish in color, this is normal, it will darken again later.
- Gently add ½ pound (225 grams) of white sugar into the blueberry puree. You can add up to a ½ pound more sugar so you have a 1 to 1 ratio of blueberries and sugar, however, although this will make your jam sweeter, in my opinion, it will also dilute the blueberry flavor. I suggest you taste the jam after the 1st ½ pound – most likely you will find it sweet enough.
- Once the sugar is fully incorporated, cover the container and refrigerate the blueberry jam mixture for at least an hour (overnight or 24 hours is even better) to allow it to macerate. Do not be concerned if the mixture is a grayish purple or dull red color, this is normal, the jam will be a dark blue or purple color after pressure cooking.
- Wash your lemon before zesting it. If you use either a Citrus Zester or a Microplane, you should get just the surface of the lemon, and a nice, fine shred that will disperse easily throughout your jam. You can also use a Vegetable Peeler, but you’ll need to press down very lightly on the lemon, or you may get some of the bitter white pith as well as the outside of the lemon skin, which is where the desirable essential oils are. If you do, flip the pieces of peel over, scrape the white part off the back, and discard the white. Then use the knife to finely cut the yellow pieces of lemon peel.
- Cut the lemon in half. Use a Manual Juicer or Citrus Reamer to juice your lemon. Remove and discard any seeds. You should have about 2 tablespoons of juice when you’re done.
- Remove the jam mixture from the refrigerator and add to the pressure cooker pot. Add the lemon juice to the blueberries, and use your spatula to stir to incorporate. With the lid OFF, turn the machine to the BROWNING setting and bring the jam to a boil. Boil for 3 minutes, stirring frequently. Don’t worry about any “scum” that forms at the top around the edges, this is normal, and it will disappear as the jam is processed.
- After the blueberry mixture has boiled for 3 minutes, add a tablespoon of butter, stir to incorporate, and turn the unit off. Put the lid on the pressure cooker and cook at HIGH PRESSURE for 8 minutes using NATURAL PRESSURE RELEASE. DO NOT force early pressure release, this could actually suck hot, sticky jam up into your pressure release valve.
- Once pressure has released naturally, unlock and remove the pressure cooker lid, holding it over the bowl at an angle to allow any hot liquid to fall back into the pot. Turn off the “Keep Warm” setting. Add 1 teaspoon finely cut lemon zest, ¼ teaspoon lemon extract and a pinch of cinnamon (the latter is optional). If you reserves whole berries to make the jam more like preserves, add them now, either whole, or you can cut them in half first. With the lid off, set the pressure cooker on the BROWNING setting, and bring the jam back up to a boil for 3 minutes. After 3 minutes at a good boil, turn the machine off and let the jam cool down. Once cool enough to handle, remove the jam to a container and refrigerate.
ZESTING TIP: Be sure and hold your head back away from your work, or wear your glasses, when zesting citrus. The same volatile oils that make the citrus zest fragrant and flavorful also contain citric acid, which can cause irritation or a burning sensation if they get in your eye. (Trust me, I know from personal experience it can happen if you’re not careful.)
JUICING TIP: I don’t remember where I read this, but they actually did a study to see which of the methods of juicing citrus was most effective, and got the most juice out of the fruit. Guess what? Old fashioned manual citrus juicers and reamers. You pay good money for your citrus, use a juicer or reamer to get the most out of them. If you have extra juice after making your liquid, you can pour it into an ice cube tray and freeze it for future use.
BLUEBERRY TIP: Blueberries are a great natural dye, intentional or not, and can easily stain your hands and permanently stain your clothing. (See my recommendations re disposable gloves.) I recommend you wear an apron and old dark clothing or clothing you won’t mind getting stains on. If you do get blueberry stains on your apron or clothing, immediately after getting the blueberry juice on your clothing, grab a bottle of Dishwashing Liquid and rub a generous amount of the liquid (undiluted) into the stain and the area of clothing around the stain. Dishwashing liquid is a surfactant, and will help prevent the molecules in the blueberry juice from adhering to the cloth. (Of course, this is a temporary measure, you’ll want to wash the affected clothing as soon as you’ve finished preparing the jam.)
- 1 pound (450 grams) blueberries (fresh or frozen)
- 1 /2 to 1 lb. (225 to 450 grams) granulated sugar
- 1 washed lemon (including zest)
- ¼ teaspoon lemon extract
- 1 tbs. butter (optional, vegans can omit)
- pinch of cinnamon (optional)
- For frozen blueberries, thaw the berries before use. For fresh blueberries, inspect the blueberries, removing any stems or leaves. Discard any berries which have shriveled, are damaged, have softened, are leaking juice, or appear to have mold. If you have more than a pound of blueberries, sort them by size, reserving the larger berries for other uses, and use the smaller berries for your jam. If any blueberries have "red" shoulders (see photo in Step 1 above), they are underripe, and should be added to the "jam" berries.
- Immediately before using the blueberries, rinse them in a fine mesh strainer or colander.
- Add the blueberries to your food processor or blender. If you want chunkier jam, more like preserves, you can reserve some of the berries to be added after pressure cooking (Step 13).
- Pulse the berries a few times, remove the lid, scrape down the sides of the bowl with a spatula, and replace the lid.
- Continue to pulse the jam mixture, removing the lid periodically to scrape down the bowl sides, until the berries are pureed.
- Once the jam mixture is smooth, remove the food processor blade, and use your spatula to remove the mixture to a bowl or container. Don't worry if the mixture has turned a muddy red color, it will change back to a dark blue color later.
- Add ½ pound (225 grams) of granulated sugar to the jam mixture. Stir to incorporate. You can add another ½ pound of sugar if so desired, but although it will sweeten the jam even further, it will also dilute the blueberry taste.
- Cover the container and refrigerate the blueberry jam for at least an hour. Overnight or 24 hours is better.
- Wash your lemon. Use a Citrus Zester, Microplane or Vegetable Peeler to zest the lemon. For best results, don't press too deeply: you want the very surface of the peel, the yellow part that is full of fragrance and oils, but not the bitter white peel beneath it. Finely dice the lemon peel, if needed.
- Use a knife to cut the lemon in half. Use a Manual Juicer or Citrus Reamer to juice the lemon halves. Discard any seeds.
- Add the refrigerated jam mixture to the pressure cooker pot. Stir in the lemon juice. With the lid off, set the pressure cooker to BROWNING and bring the jam mixture to a good boil. Boil for 3 minutes. (You can ignore any scum that forms at the surface, it will disappear after being pressure cooked.)
- Turn the pressure cooker off. Stir 1 tablespoon of butter into the jam mixture. Pressure cook at HIGH PRESSURE for 8 minutes using NATURAL PRESSURE RELEASE. It is very important that you don't force early release of pressure, it could cause problems in your pressure release valve.
- Once pressure is released, turn off the unit, and remove the lid, holding it at an angle over the pot to allow any hot liquid to drop back into the bowl. Add 1 teaspoon of grated lemon zest, ¼ teaspoon of lemon extract and (optionally) a tiny pinch of cinnamon. If you have reserved some berries, you can add them (either whole or halved) at this point. With the pressure cooker lid off, set the unit on BROWNING and bring the jam up to a rolling boil for 3 minutes, stirring frequently. Turn the machine off. Allow the blueberry jam to cool at room temperature, then put in a lidded storage container, and refrigerate.