Recipe from Browncookie.com
800 g of white granulated sugar
290 g of water
2 lemons (to yield 6 tablespoons of lemon juice)
2 tablespoons of white vinegar
1/4 teaspoon of baking soda mixed with 2 tablespoon of water (Set aside in a small dish)
1. Wash the lemons and squeeze out all the juice into a bowl. Set the juice aside and measure out 6 tablespoons. Then, cut the lemons into quarter wedges and set aside.
2. Next, in a small sauce pan, add sugar and water and boil on high heat until the sugar has completely dissolved. Stir to mix frequently.
3. Lower the heat to a simmer and add lemon juice, lemon wedges and vinegar (This is the acidic component of the syrup). Stir occasionally.
4. Insert a candy thermometer and continue to boil on medium heat until the solution reaches 108⁰C. Now, you may think that since boiling point of waster is 100⁰C and since 8 degrees is only a small increment higher so this process should only take a few minutes. But that would be wrong. The solution at this stage is very saturated with sugar and acid. In order for the solution to absorb enough energy or "heat" (Chemistry folks you will remember q=mCΔT, Sorry, I couldn't resist! For the rest of us, this is just a scientific equation that shows the relationship between heat and time needed to raise temperature in a solution.) To get the solution up to 108⁰ C is going to take about 30 minutes or more. You have to trust the reading on the candy thermometer. Along the way to this temperature, the sugar solution will automatically turn into a golden color.
5. Once the thermometer indicates 108⁰C, turn off the heat. Stir in the baking soda solution.
6. At this point you will notice bubbles coming up to the surface of the solution. Once the solution cools, it will disappear. Let the solution cool in the sauce pan and strain into the storage jar (preferably glass). Best used within a month. Keep refrigerated.