Blend Raspberries: Put the raspberries in a food processor and blend until smooth.

Strain Juice: Pour the raspberry puree through a fine mesh strainer, keeping the juice and discarding the seeds.

Combine Ingredients: In a large pot, mix the raspberry juice, lemon juice, sugar, and lemon zest (if using). Cook over medium heat until the mixture reaches 190°F, stirring to dissolve the sugar and making a simple syrup. Avoid boiling.

Cool: Allow the concentrate to cool slightly before canning.

Sterilize Jars: Wash jars, lids, and bands in hot, soapy water. Simmer jars in a water bath canner for 10 minutes. Keep lids and bands hot but not boiling.

Prepare Canning Station: Set up your ladle, canning funnel, jar lifter, and clean cloths within easy reach.

Fill Jars: Using a canning funnel and ladle, fill the jars with the hot concentrate, leaving a ¼-inch headspace. Remove air bubbles with a spatula.

Wipe and Seal: Clean the jar rims with a damp cloth. Place the lids on the jars and screw the bands on until fingertip tight.

Process: Place jars on a rack in the canner, ensuring they’re covered by at least 1 inch of water. Boil for 15 minutes (adjust for altitude). Let jars cool in the canner for 5 minutes before removing.

Cool and Check Seals: Let jars cool on a towel for 12-24 hours. Check seals; the lid should not flex when pressed. Label and store in a cool, dark place.

Dilute the Concentrate: In a glass pitcher or tall glass, mix the raspberry lemonade concentrate with water. The typical ratio is 1 part concentrate to 3 parts water, but you can adjust this to your taste. For a single serving, start with ¼ cup of concentrate and add ¾ cup of water. Taste and adjust as you would like.

Chill (Optional): For an extra refreshing drink, chill the mixed lemonade in a large pitcher in the refrigerator for 30 minutes to an hour (perfect to prep for a large crowd), or serve immediately over ice.