Blanch the peaches in boiling water for 30 to 60 seconds, then transfer to a bowl of ice water. Slip off the skins, halve the peaches, and remove the pits.

Chop the peeled peaches and place them in a heavy-bottomed pot with the water, bottled lemon juice, and lemon zest. Cook over medium heat, stirring occasionally, until soft and broken down, about 20 minutes.

Blend smooth using an immersion blender, food mill, or food processor. Measure the puree against the recipe's target.

Return the puree to the pot and stir in the sugar until it dissolves. Bring to a boil over medium-high heat, then reduce to a gentle boil and cook, stirring often and scraping the bottom, until thickened and it mounds on a spoon. The butter thickens further as it cools, so stop slightly early.

Ladle the hot butter into prepared jars, leaving 1/4 inch headspace. Remove air bubbles, wipe the rims clean, center the lids, and apply the bands fingertip tight.

Process in a boiling water bath for 10 minutes for half pints or pints, adjusting for altitude (see notes).

Turn off the heat and let the jars stand in the canner for 5 minutes, then remove and cool undisturbed for 12 to 24 hours. Check seals before storing.