Wouldn't it be nice to have a sugar-free summer drink, made with ingredients from your own garden? Easily accomplished!
Step 1: What Is Stevia?
Stevia is a south American plant that has been grown for hundreds of years because of its intense natural sweetness. Just how sweet is it? Stevia is 150 times sweeter than sugar, comparable to aspartame (which is 200 times sweeter than sugar), but unlike other non-sugar sweeteners, stevia doesn't require any special equipment of techniques to make it. It's non-toxic, sugar-free, low carb, and all those other fun organic words. Gluten-free.
Stevia seems to grow well enough in my Northern Virginia climate, requiring no care on my part other than the occasional semi-neglectful watering. If you are reading this in North America, the odds are good that you'll be able to grow stevia without trouble. (though those of you in northern Canada and Mexico may have to make some weather adjustments.)
The ideal time to harvest is in the fall, when the sweetness-causing chemicals will be concentrated in the leaves. I grabbed some early to make a drink for a friend who has a slight case of diabetes.
Step 2: Tincture Basics
A tincture is just an old-timey way to extract a certain flavor or property from herbs, and make them more readily available. The process is similar to making a tea, with the difference that alcohol is used instead of water.
Using alcohol allows more of the chemical compounds to be extracted. You can use water, but you can expect that you will get less of the sweetness from the leaves. The goal is to create a highly concentrated sweet liquid that can be added to drinks instead of sugar.
You can see that I picked about half a cup of leaves, and that I have about a cup of alcohol. You'll want a tasteless, fairly pure alcohol for this, so I used a basic vodka.
Combine and shake gently. You want to get the leaves thoroughly wetted by the alcohol, and keep them that way. Shake every so often. I kept mine for about 36 hours this way.
Step 3: First Extraction
After waiting a day or two, I strained the leaves out. Waiting too long won't substantially improve the strength or sweetness of your tincture in this case, but it can make it more bitter. I find that stevia has a mildly unpleasant flavor- very "green", or vegetal. Some people have compared it to licorice. I don't want that flavor, so I make sure to strain out fairly early.
I dump the leaves into a colander and let the liquid drain into a bowl below. I press the leaves gently to squeeze out the remaining alcohol but not to an extent that the begin to break apart and leave large particles.
You can see that the alcohol has turned a striking green color- evidence that we have extracted something!
Step 4: Second Extraction
We aren't done yet- though we could be. I want to make sure that I have a potent, super sweet tincture that only needs a drop or two to be noticeable in a beverage.
So on to round two! Same as the first- pick more leaves, and add them to the existing alcohol. The liquid level has decreased due to a combination of evaporation and being absorbed into the first set of leaves, so I use slightly less fresh leaves this time. Again, the goal is to get the leaves covered.
After a day or two of gentle shaking, I run them through the colander again and am left with a sweet green liquid.
Step 5: Put in Glass Dropper Bottles
You now have a very sweet liquid that is suitable to add to drinks, and some cooking recipes. You'll only need a few drops to flavor your beverage, which is good, because there is still quite a bit of alcohol content in there.
If that bothers you, you can try heating the tincture in a water bath for 20-30 minutes, which should evaporate a lot of the alcohol away, and may the liquid even thicker and more concentrated. If you do this, let me know how it compares to the unheated version, as I have not done that step.
Enjoy your sugar-free tincture!
Step 6: Bonus: Lemon Balm Sun Tea
What should we use our sweetener on? How about a very mild lemon balm tea, harvested from the herb plant growing next to the stevia?
Lemon balm is a pleasant herb with an intense citrus smell when crushed. It is hardy and seems to need even less attention than the stevia does. Some claim that it has various health benefits, but I just enjoy the scent.
This is prepared just like any other sun tea, with leaves placed in the warm sun for several hours. This makes a very mild flavored tea, but still retains the smell. You can add lemon juice to give it a more potent lemon taste.
And of course, you can sweeten to taste!