Making delicious jam can be deceptively simple if you prepare it with the streamlined technique I have perfected over the decades I have been raising red raspberries. Several shortcuts have been introduced, but certain steps must be carefully followed to avoid messes…
Fruit is particularly amenable to canning because of the acid it contains. Further, sugar added in high concentration is a very good preservative. I add high amounts of sugar up front which minimizes the boiling step (many recipes call for extended boiling to reduce the volume). This shortened boiling preserves the flavor compared to “reduction” boiling.
I have used this procedure with great success with other fruits. They all contain between 84% and 90% water. Those with higher water content may require slight adjustment of the sugar (step 10). Water content, according to the Composition of Foods: Red raspberries 84%, strawberries 90%, peaches 89% and apricots 85%. If the fruit you are using is higher than most in water, you may have to increase the amount of sugar to compensate.
Supplies
2 cups perfectly ripe berries, picked over
2 cups granulated sugar
Equipment
2 cup measure
one gallon pot with lid
two pint mason jars with lids
tongs
1/2 gallon stainless steel pot
whisk
thermometer, reads 120 to 240 F (-10 to 110 C)
canning funnel
Directions
Pick a pint of fresh berries, fully ripened.
If necessary pick through the berries to remove less than perfect berries, leaves, stink bugs, etc… (;-)
Place the Mason jars with lids and rims in a gallon pot. Add an inch of water to the bottom, cover securely, bring to a boil for 10 minutes.
Pour the berries into a quart pot. Measure an equal volume of granulated sugar to the berries you have (one pint in this case).
Pour the sugar over the berries.
With a stiff whisk, thoroughly mix the sugar into the berries. Stir into the corners of the pot to wet any pockets of sugar hiding there.
The mixing should draw out juice so that the entire mixture becomes wet.
Place the stirred mixture of sugar and berries on the stove, add a thermometer and apply medium heat with stirring.
Bring the mixture to a boil. Reduce the heat and heat until the “oily” liquid rises to near the top of the pot. DO NOT BOIL OVER!
The temperature should be 104 C if the proportions of sugar and berries was correct. If the temperature is less than 104 C, you may add sugar tablespoon by tablespoon full until it does boil at 104 C. Be aware that boiling sugar solutions will burn you quickly and seriously!
CAUTION: BOILING HOT JAM!: With great care (again, this boiling mixture can burn the heck out of you!) pour the boiling hot mixture into the sterilized jars. A canning funnel (not used here) makes for less mess. My canning funnel is aluminum, and because of the acid of the jam, I choose not to use it.
Immediately cover the boiling hot jam with a sterile lid, secure lightly with a rim. Allow to cool about 10-15 minutes. The lid will pop down.
Several minutes after the lid has popped down, gently swirl the jar to see that the vacuum created holds tightly. If the lid does not pop up, tighten the rim, and gently invert the jar. The purpose is to ensure sterilization of the lid with the still hot jam. If you invert too soon, jam leaks out…
When the jars have cooled enough to hold in your hand (about 30 minutes?) turn right side up. Remove the rims and clean off any jam that may have leaked out. Replace the rims and label with the date made and fruit used.
David Fankhauser 