Author: Ball Complete Book of Home Preserving (2006)
Ingredients
7 cups granulated sugar
8 cups whole strawberries (approx.)
4 Tablespoons freshly squeezed lemon juice
1 package (1.75 oz./49 to 57 grams) regular powdered fruit pectin
½ teaspoon butter (helps reduce foaming)
One large vanilla bean, halved and split in half lengthwise. Do not scrap out beans.
Instructions
Sterilize 8 to 10 8-ounce mason jars by placing water in a water canner or electric canner that is at least 3-inches deeper than the height of the jars. Cover and bring water to a simmer but do not boil, keep jars warm. Prepare lids by simmering gently in a small saucepan. Do not let boil; keep warm. Set clean screw bands aside (do not simmer them.)
Measure sugar into a bowl and set aside. Wash strawberries in cool running water. Drain thoroughly then remove hulls. In a glass pie plate or other flat-bottomed bowl, place a single layer of strawberries. Using a potato masher, crush berries and transfer to a 1-cup liquid measure. As you accumulate transfer crushed berries to a large deep stainless steel saucepan. Repeat until you have 5 cups of crushed berries.
Add lemon juice to crushed berries in pan. Whisk in the powdered pectin until dissolved. Add the ½ teaspoon butter and the vanilla bean half.
Bring to a full rolling boil over high heat, stirring frequently. Add sugar all at once, stirring constantly, and return to a full rolling boil that can't be stirred down. Boil hard, stirring constantly, for 1 minute. Remove from heat and using a large slotted spoon, skim off foam. Remove vanilla bean.
Fill one sterilized and warm jar at a time; removing jar from canner and empty hot water back into canner. Do not dry jar. Place jar on a tray or towel-covered counter and place a canning funnel in jar. Ladle hot jam into hot jar, leaving a ¼-inch headspace. Slide a non-metallic utensil down between the jam and inside jar two or three times to release air bubbles. Adjust head space, if necessary by adding more jam. With a clean damp cloth or paper towel, wipe jar rim and threads to remove any jam residue. Place warm lid centered on top of jar, and place on screw band down evenly and firmly, making fingertip tight. Return jar to canner rack and repeat until all jars are filled.
Cover canner and bring water to a full rolling boil over high heat. Process for 10 minutes, starting timer only when water reaches the full rolling boil. Turn off heat and remove canner lid. Wait 5 minutes, then remove jars without tilting. Place jars upright on a towel in a draft-free place and let cool, undisturbed, for 24 hours.
After 24 hours and check lids for seal. Remove screw bands and press down on the center of each lid. Sealed lids will be curved downward and show no movement when pressed. Jars that haven't sealed must be refrigerated immediately. Wipe jars; rinse and dry screw bands and loosely apply. Label jars and store in a cool, dry place.
Recipe by The Culinary Cellar at https://theculinarycellar.com/strawberry-vanilla-jam/