I've played with these but mostly nowadays I just like my Tonic.
http://lesssugarnaturally.blogspot.com/2013/01/Homemade-Stevia-Soda-Pop.html
here's the recipe I use and what I do for tonic syrup:
Tonic Syrup
Recipe:
4 c. water
3-4 lemongrass stalks chopped
1/4 c. cinchona bark
zest and juice of one grapefruit
zest & juice of 1 orange
zest & juice of 1 lemon
zest & juice of 1 lime
5 allspice berries
1 tsp dried lavender
5 cardamom pods, slightly crushed
1/4 tsp black peppercorns
1 small star anise
1/4 c. citric acid
1/4 t. kosher salt
Combine and boil slowly 20 min. Strain through a sieve and a French Press.
add 1 1/2 cups simple syrup
Stevia simple syrup:
1/4 cup or even less, stevia
2 cups water.
Bring water to a boil and then add stevia. Mix until dissolved and remove from heat. Let cool.
1. Pour the water into a medium-sized nonreactive saucepan. Add the zest from the grapefruit, orange, lemon, and lime. (You can remove it with a sharp vegetable peeler, in strips, or with a citrus zester.) Halve, then juice the citrus fruits and add the juice to the saucepan.
2. Add the lemongrass, citric acid, chinchona bark, allspice, cardamom, star anise, salt, and black peppercorns. Bring the mixture to a boil and reduce to a simmer. Cover with a lid, leaving it slightly askew, and let it simmer gently for 15 minutes. Remove from heat, uncover, and cool to room temperature.
3. Pour into a container, such as a large screw-top jar, and chill for 2 days in the refrigerator, shaking it gently a couple of times a day.
4. Strain liquid through a fine mesh strainer, preferably into a large measuring cup (which will make the next step easier). Discard the spices, lemongrass, bark, and citrus peels. Strain the mixture again, this time through a strainer lined with several layers of cheesecloth, muslin, or a coffee filter. (If using a coffee filter, it’ll remove most traces of the spice powder but it’ll take a bit of time, so be patient.)
5. Add the sugar syrup, then pour into clean bottles or screw-top jars and refrigerate until ready to use.
For my part, I’ve taken to decanting to do most of the straining work for me. I used to put coffee filters on every clean dish I could find, running around to keep the filters from clogging or breaking, but that got old quick. Now I put my post-boil “soup” through a fine-mesh metal strainer, then let it sit (covered) overnight in a wide-base wine decanter in the fridge. The sludge settles out pretty well, and while I might be ending up with less final product than I would with patient filtering, the simplicity makes it totally worth it.
I boil the bark by itself for about 30 minutes and filter that with the coffee filters- goes really fast (4 cups of water, reduced down to about 2) and then add that into a pot with another two cups of water and use Organic Erythritol as the sweetener- no calories, no nasty aftertaste- in fact,
The filtering process has always been time consuming and messy but this year I found some good techniques that reduce the process to about a half hour. After cooking the tea I strained it through a wire sieve to get rid of the lemon grass and fruit zest, etc. I put it back in the pot, put a cover on it and left it on the stove overnight to settle.
Today I skimmed off the liquid with a ladle and put it through a coffee filter press. When I got to the “mud” at the bottom of the pot I layered about four paper towels and formed a cone with it. I poured the mud into it and gently squeezed out the liquid with my hands until all that was left was a thick cinchona paste in the towels.
Back on the stove to heat, added the sweeter and all done. I no longer dread running out of syrup since I’ve cut the prep time in half.