Thoroughly wash the apples, then cut them into 1-inch pieces to prepare them for juicing.

Bring the 10 cups of water to a boil in a large pot, then add the apple pieces. Stir in the cream of tartar, ensuring it dissolves evenly.

Cover the pot with a lid and reduce the heat to low. Allow the mixture to simmer gently for about 15 minutes until the apples begin to break down and soften. After simmering, remove the pot from the heat and let it cool to room temperature. Leave the mixture to rest for 24 hours, allowing the flavors to deepen and infuse.

Once cooled, strain the liquid into a large jar, pressing firmly on the apple pulp to extract every last drop of juice. Stir in the sugar and lemon juice, adjusting the sweetness to suit your taste.

At this point, you can seal the juice by placing a sterile lid on the jar for long-term storage, or proceed to the next step if you prefer it fresh. Place the jar in the refrigerator and let the juice settle. Over time, the liquid will naturally separate, leaving a sediment layer at the bottom and a clear, rich juice on top. Carefully pour the clear juice into another jar, discarding the sediment.

Chill the juice thoroughly before serving. Enjoy your homemade apple juice!