Sterilize/heat the canning jars in simmering water. Prepare jar flat lids and screw bands according to manufacturer's instructions. Fill a water bath canner with water, per manufacturer's directions; bring water to a simmer on Low heat.

Pour cider (or juice) into a large saucepan. Bring juice to a boil, then reduce heat and keep it warm while you fill the jars.

Rinse/drain fresh cranberries. Measure 1¾ cups of cranberries into EACH sterilized, hot jar. Jars will not be full. Add ¼ cup sugar into EACH jar. Carefully pour warm cider/juice into EACH jar, using a canning funnel for less drips! Fill jars, leaving a ½" headspace in each jar.

Remove air bubbles from jars by inserting a skewer or plastic knife into each jar around the edges. Adjust headspace, if necessary (remove or add juice). Wipe the rim of each jar clean with a clean, damp cloth. Place a flat lid on each jar, add the screw band, then tighten until band is fingertip tight.

Carefully place jars on a canning rack into a water bath canner (with simmering water inside). Lower rack into the hot water. IMPORTANT: Make sure jars are covered by 1" of water above the jar lids, adding additional hot water, if necessary. Cover canner. Bring the water to a rolling boil, THEN set timer for processing. Process quart jars for 20 minutes. Keep water at a gentle boil throughout the processing time (you may have to reduce the heat slightly).

Once the jars have been processed, turn off the heat. Let jars rest 1-2 minutes, then carefully remove the lid. Use canning tongs to transfer hot jars onto a dish towel to cool. IMPORTANT: Do NOT put the hot jars directly on the counter, because temperature variances could cause jars to crack or break. Let jars cool to room temperature, undisturbed (about 12 hours). You should hear the lids "pop" or "ping" as each jar seals and becomes airtight. Once jars have cooled completely, check to ensure each jar is sealed. The lid should have no flexibility on top when you press down on it with a finger. Remove the screw band from each jar for storage.

Store sealed jars in a dark place in the pantry for 4-6 weeks as the juice develops flavor and color. Once a week, carefully flip each jar upside down and then turn quickly right side up. This helps infuse the extracted cranberry juice (and red color) into the liquid. As the jars sit (and are flipped) during the 4-6 weeks, the sugar will begin to extract juice from the cranberries. You will notice the color of the juice darkening to a beautiful red color as time goes on.

After the 4-6 weeks, the juice is ready. Open a jar; remove cranberries from the juice (see my blog post for how to use the cranberries!). To serve, pour juice over ice and enjoy. TIP: If you want to make the juice bubbly, add a small amount of sparkling water to each glass; stir to combine. Cover and refrigerate any open jars of juice. Canned juice (unopened jars) can be stored for 12-18 months.