Sunday, August 04, 2013

We be jammin' : The blueberry edition

The legendary Bob Marley: The music for my morning!

So a bunch of folks wanted to know my process for making blueberry jam. I posted some of the following photos on G+, but I thought I'd take you through the whole process from berry to jam in the jar. Enjoy!

First off, I do a lot of experimenting with small batch jams. As long as you understand the basics of the process and don't shortcut the important stuff (high quality not over-ripe fruit and good sterilization of your canning supplies), you can definitely play with sugar content and flavors.

Second, I almost NEVER use added pectin in my jams and preserves. That allows me to use less sugar and let the fruit shine and gives a softer-set jam, which I prefer anyway. Most just-ripe fruit will have enough pectin in it to set and using a little bit of under-ripe fruit or adding a grated apple to your jam will give you a firmer set if you like that better.

Third, small batch is the way to go. Just enough fruit to fill the jars that will fit in one canner load will allow you to get the set just right. 

Here's the recipe. Step by step with photos below:

Lisa's Blueberry Basil Preserves

3 pounds washed blueberries, stems and over-ripe berries discarded
1 to 1 1/2 pound sugar
1-3 TB lemon juice (can use lime juice and zest instead for a different flavor profile)
Lemon zest
Fresh basil (optional)
1-3 TB Balsamic vinegar (optional)

Yield--6-7 half-pint jelly jars

  • Let berries and sugar macerate overnight.
  • Drain sugar/water slurry into a non-reactive, thick bottomed pot
  • Add lemon juice and zest, balsamic if desired. 
  • Set berries aside
  • Bring sugar mixture to a boil for about 10 min, stirring well
  • Skim foam, if desired (a TB of non-salted butter added to the pot reduces foaming)
  • When the sugar mixture nears the jelling point (see this link for spoon test), fold in the berries and any remaining liquid.
  • Check taste and add add'l lemon/zest/balsamic to your preference
  • Bring to a boil again.
  • In 5-10 minutes, it should reach the jelling point.
  • Can and process 10 min in a water bath.

Step one: Drag your family to pick blueberries. :)

Here's a truism about canning--the food in the jar will be no fresher than the source material you start out with. If you're going to go through the work to make your own preserves, get the best, freshest berries you can.

Make sure to stay away from ones that are over-ripe. The riper the fruit, the less pectin it contains. Firm berries that come off easily from the bush are what you want. 

It takes about 3 pounds of berries to make 6 half-pint jars of preserves, so plan accordingly. 

Step Two: Weigh out 3 pounds. (A kitchen scale is really your friend when you can. Volume measurements are really inaccurate) Wash the berries, discarding sticks and stems and any mushy ones. Place in a bowl with 1 to 1 1/2 pounds of sugar. (Most commercial jams are 1:1 by weight fruit to sugar. Too sweet, by far, for me.)

Mix the sugar with the fruit and cover. Let sit a few hours or place in the refrigerator overnight. This step is called maceration and is the secret to a very fresh-tasting jam. This will pull the water from the fruit and leave you with the berries floating in a sugar/water slurry.

Optional step: Pick some basil from your garden.
Wash it and toss it whole in your sugar/berry mix. A great flavor combo!

Step three: A few hours later, or the next day, put the berry mix in a colander and let the water/sugar mixture drain into a large non-reactive pot. (I love my enameled cast-iron pot--the thick walls means no scorching! ) You need a large pot because when you cook your jam, it will boil up a lot.

Set the berries aside. If you used basil, pick it out now.

Step four:  Fill a large pot (large enough to fit your canning jars with at least an inch of space between the top of the jar and the top of the pot) with hot water, line with a silicone mat or trivet of some kind and place on the stove. Bring the water to near boiling.

Wash your jars and supplies (wide mouth funnel, jar tongs, and lid lifter) in hot, soapy water.

Prepare a few more jars than you think you'll need, and make sure you have enough lids and bands to go with them. **Bands you can re-use over and over. Lids are single use only!**

Rinse the jars well and place them in the canning pot. The boiling water will keep them sterile until you're ready to use them.

Place bands and lids in a smaller pot filled with water, bring to a simmer and let sit.

Step five: Once it reaches the jelling point, turn heat to simmer and ladle hot mixture into your half-pint jelly jars. Make sure you leave 1/4 inch space between the jam and the top of the jar ('head space').

Wipe outside of rim with a damp cloth.

Using the lid lifter (it has a magnet) lift out one lid and place it on the filled jar. Repeat with band, tighten band gently--finger tight only. Pick up filled jar with jar lifter (the funny looking tongs) and place in hot water bath. Repeat with next jar until you run out of jam.

Bring water in the canner to a full rolling boil. Set a timer for 10 minutes. When it's done, CAREFULLY lift the jars from the hot water bath and place on a cutting board to cool. Do NOT fiddle with the jars. The jelly may seem loose-set for several days.

Voila! Blueberry preserves cooling on the counter!


  1. I am definitely doing this. Saw your post and FB and thought I'd go looking for a "how-to" on saved me the effort.