Harvest rhubarb and remove the leaves.
Wipe down rhubarb with a wet cloth.
Cut rhubarb into 1" pieces.
In a saucepan over medium-high heat, bring the rhubarb & water to a boil.
Lower to medium-low, cover, & cook for 10 minutes. Stir occasionally to break fruit apart & allow all the juices to be released.
Pour rhubarb mixture through a fine mesh strainer lined with a double layer of cheesecloth.
Gather the extra length of the cheesecloth and twist to push the juice out. Use a wooden spoon to press the juice out.
Measure the rhubarb juice. If you have 3+ cups of juice, proceed. If you have less than 3 cups of juice, add water to make it 3 cups.
Put the liquid back into the sauce pan over med-high heat. Stir in sugar & bring to a boil. Boil for 6-8 minutes.
Remove from heat, stir in lemon juice. Optional: strain again for clearest syrup
Let cool & store in the fridge or immediately ladle hot syrup into jars (leaving ¼” of headspace) and water bath can for 10 minutes.