Add sugar, lemon juice, water and lemon zest to a saucepan.
Heat over medium heat and stir until the sugar has dissolved.
Bring the syrup to a boil, then take off the heat. This syrup will be quite thin. If you want a thicker consistency, simmer the syrup until it gets to the consistency that you want. Be careful not to let it burn.
To make lemonade with this syrup, mix 1 part of this lemon syrup with 3 to 4 parts of cold, sparkling water.
If you are wanting to can this recipe, follow proper canning rules. Ladle into sterilised jars, leaving ½" head space. Wipe the rim of each of the jars with wet paper towel, place lid on and tighten. Place in canning pot and water bath for 15 minutes. For best long-term storage, keep jars in a cool, dry and dark place and use within a year.
Nutritional information is an estimate and provided as a courtesy. The values may vary according to the ingredients and tools that are used. Please use your preferred nutritional calculator for more detailed information.