Rinse the pineapple under cold water to remove any dirt or impurities. Cut off the crown and the base of the pineapple. Stand the pineapple upright and carefully slice off the tough outer skin, making sure to remove any "eyes." Cut the peeled pineapple into chunks, discarding the tough core.
Peel the skin off the ginger. Cut the ginger into smaller pieces for easy blending. Core and peel the apple and cut it into chunks. Squeeze the lemon juice into a bowl and set aside.
Place the pineapple chunks, ginger pieces, lemon juice, and apple chunks into the blender. If using a high speed blender, add a small amount of water (around 1/4 cup) to facilitate blending. If using a juicer, this step is not necessary. Blend or juice the ingredients until you achieve a smooth consistency. If the juice appears too thick, add more water and blend again until you reach your desired consistency.
If you prefer a smoother texture, strain the juice through a fine mesh strainer into a large bowl or pitcher.
Serve and enjoy your homemade pineapple ginger juice