Wash and dry your lemons. (use only water to wash the lemons) 

Peel the lemons with a vegetable peeler (peel as thin as possible and try not to get too much of the white pith under the peel - it's really bitter)

Put the peels into a large glass sealable jar. Add the alcohol and make sure that it completely covers the peels. Let the mixture steep for 7-8 days

After the infusing period, strain the peels through a fine mesh sieve

In a large saucepan, combine the water and sugar and bring to a boil. Once the sugar is dissolved, and the syrup is clear you can remove it from heat. Let the syrup cool to room temperature

In a one liter sealable bottle, combine 10 oz of the infused grain alcohol with 20 oz of the simple syrup. Seal, shake well and refrigerate