how to make jam (with a recipe for raspberry-vanilla jam)

Making jam has given me a new appreciation for summer and a greater appreciation for the very brief growing seasons of fruits like strawberries, blackberries and raspberries.  I savor these fruits more so than before and I’m excited that I’ll be able to enjoy them again this winter thanks to the jam-making and canning skills that I learned from Happy Girl Kitchen Co.’s jam-making workshop.  (Food in Jars is another inspirational and informative resource.)

Making jam seems to involve two mysteries: (1) making the jam, and (2) safely canning the jam.  I’m still a novice, but the task really is quite simple once you try it and gain confidence!  I learned from my workshop that fruit is the safest thing to first try canning because fruit is naturally acidic and therefore less prone to botulism.  Boiling the jam kills off bacteria, and so the only remaining “issue” is to ensure a proper seal when you hot-water-bath the jars of jam.  So long as you can see that the lid is sealed, you’re in the clear!  Please give it a try — making jam is so satisfying and addicting!

I learned some basic jam recipes from Happy Girl Kitchen that are low in sugar and do not call for pectin.  Fruit naturally contains some pectin (important for causing the jam to gel) and sugar is also instrumental in creating gel.  Many recipes call for a ton of sugar — many I’ve seen call for equal parts sugar and fruit! — but that much sugar really isn’t necessary and it can drown out the flavor of the fruit.  Sugar absorbs moisture and so it assists with creating gel, and it is also a natural preservative.  The recipes that I use call for just enough sugar to lend sweetness to the fruit and to create gel; more sugar would ensure a longer shelf life once you’ve opened the jar, but it won’t last very long anyway!

raspberry-vanilla jam

makes 7 half-pints

Time required: About 2 hours

1 flat of organic raspberries


5 pounds of raspberries (or other bush berries, e.g., blackberries, blueberries)

2 pounds of evaporated cane juice (a.k.a., “raw sugar”)

1/2 cup of lemon juice (freshly squeezed or use bottled Santa Cruz Organic brand)

1 Madagascar bourbon vanilla bean (optional)


a large tub or other container large enough to contain the fruit (I use the crock with lid from my slow cooker)

kitchen scale

large stock pot

potato masher

wooden paddle or extra long wooden spoon

rubber gloves

3-4 small clean plates, in the freezer

hot water canner (large pot and canning rack)

half-pint mason jars (cleaned and dried) with new lids

jar funnel and ladle

Sharpie or other magic marker


Prepare the fruit:  On the night before the day when you plan to make the jam, wash the raspberries and put them in a large lidded tub (I use the lidded crock that came with my slow cooker).  Add 2 lbs of raw sugar and 1/2 cup of lemon juice to the fruit and stir to combine.  Put on the lid and let the fruit macerate over night.  The berries will release liquid and this will give a jumpstart to the process of cooking down the fruit into jam.

raspberries and their liquid, after sitting in lemon juice and sugar over night

The next day:  Clean the jars and set aside.  Put the small plates in the freezer.  Put on rubber gloves to protect your hands and arms from hot jam splatters.

Pour the contents of the berry tub into a large stock pot and mash the berries with a potato masher.  Turn the heat on high and bring the berry mixture to a boil, stirring constantly with a wooden paddle or long wooden spoon to avoid burning the jam.  The objective is to boil off enough liquid and raise the heat of the mixture high enough to reach the gel point for jam.  The cooking time depends on how wide your pot is, but keep stirring and boiling the berry mixture until you notice that it has reduced some and has started to thicken (15 minutes or more).

We’re thickening the jam naturally using sugar and cooking time, and so it’s important to start checking for the “gel point” after you notice that the mixture has started to reduce and thicken.  To test the gel point, take a small plate from the freezer and use a small spoon to put a dollop of jam at the center of the plate.  Return the plate to the freezer for a minute.  (This process mimics what the jam will be like at room temperature.)  Retrieve the plate from the freezer and hold the plate up to allow the jam mixture to run down the plate.  The jam is “set” when it stays in a clump as it runs down the plate.

testing for the gel point

Once the jam is set, move the pot off the burner and to the side.  Fill the hot water canner with enough water to cover the jars by a couple inches and bring it to a boil.

If you are adding vanilla, cut the bean lengthwise, scrape the seeds into the hot jam and then toss in the bean.  While you wait for the hot water to come to a boil, stir the jam occasionally to allow the raspberry and vanilla flavors to marry.  Taste the jam occasionally and remove the vanilla bean when you’re satisfied with the flavor.  (I left it in for about 15 minutes.)

Ladle the jam into jars, leaving a 1/4 inch of head space.  Wipe the rims of the jars clean (this is essential to ensure a complete seal) and put the lids on the jars.  Screw the lids until fingertip tight — just until you feel resistance and the jar tries to turn on its own.  Do not over tighten the lids.

Put the jars in the canning rack and, while wearing gloves, carefully lower the rack of jars into the boiling water.  “Process” (i.e., allow to sit) the jars in the hot water bath for 5 minutes.  Then, while wearing gloves, carefully lift the canning rack out of the boiling water and remove the jars to a cutting board to cool.  Tighten the lids slightly — just an 1/8 or 1/4 of a turn — because over-tightening could prevent a complete seal from forming.

Check the lids after a few minutes.  The “button” part of the lid should be drawn inward so that the lid is flat.  If you see this, congrats!  The jars are sealed!  If any of the jars failed to seal, simply re-process them in the boiling water for a few more minutes.

Once the jars are cool enough to touch, use a Sharpie to label the lid of the jar with the contents and date so that you know what’s in the jar and when you made it.  The jar of jam can last more than a year, but every source I’ve encountered encourages consumption within a year to enjoy the best color, texture and flavor.

Finally, for all you urbanite canning virgins out there, here’s a note on canning etiquette:  If someone gives you a jar of jam, please return the jar after you eat the jam.  If you give someone a jar of jam, it is ok to say, “please return the jar after you enjoy it.”  Jars are reuseable, after all!  Return the jar, get a refill!  🙂

Feel free to leave questions in the comments and I’ll do my best to answer them!


One response to “how to make jam (with a recipe for raspberry-vanilla jam)

  1. Pingback: Food // Rosemary-vanilla rapsberry jam | stuff cYn loves

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