Wash, dry, and chop the rhubarb. Place into a large jar. Add the lemon peel and the ginger. Pour in the gin. Stir gently with a long wooden spoon.

Cover and let steep in a dark place (cupboard, pantry, cellar) for 3 to 4 weeks. Stir every day during the first week and every 3-4 days for the rest of the time.

Taste after 3 weeks, the gin should be already slightly pink and very flavorful. Strain through a fine-mesh sieve lined with a cheesecloth/ muslin cloth into a jug. Carefully pour into a bottle (you can use the original gin bottle).

Keep refrigerated and consume within 4-5 weeks. The gin will not go bad if kept for longer, but it will slightly lose the rhubarb flavor.