My standard sour mix for Whisky Sours, and anything else that calls for sour mix.
4 parts lemon juice (fresh squeezed)
3 parts homemade cane syrup (1:1 ratio of evaporated cane juice and water)
1 part water
1 part orange juice
Stir all ingredients thoroughly in a pitcher. You can then store this in glass mason jars in the freezer for up to a year. Leave a space at the top of the jar so it has room to expand when it freezes.
This recipe is calibrated for my homemade cane syrup. If you use bottled cane syrup, you may need to increase the amount of lemon juice to compensate. Bottled cane syrup will probably be sweeter.
Taste each batch after you make it to make sure the balance between sweet and sour is to your liking. The lemon juice can vary a little in tartness. Just adjust the batch if need be.