Choose firm, heavy lemons with thin, bright yellow skin. Wash under cool running water and pat dry with a kitchen towel.

Cut each lemon in half and use a citrus juicer or reamer to extract juice, pressing firmly until you have about 2 cups of fresh lemon juice.

Pour the lemon juice through a fine mesh strainer into a bowl or measuring cup to remove seeds and pulp.

Pour 1 cup of water into a medium saucepan and bring to a simmer over medium heat. Add 2 cups of granulated sugar and stir constantly until the sugar dissolves, about 3 to 5 minutes.

Remove the saucepan from heat and let the simple syrup cool for about 5 minutes, until it reaches room temperature.

Pour the strained lemon juice into a clean bowl and slowly add the cooled simple syrup while stirring gently until smooth and golden.

Stir in 1/4 teaspoon of salt and mix thoroughly for about 30 seconds.

Use a funnel to pour the concentrate into clean glass bottles or jars with airtight lids, leaving about an inch of headspace. Seal tightly and label with the date.