There are many different types of Stevia products out there. The stevia I buy is from whole and unfortunately isn't organic, but is much healthier than to load up with fructose and sucrose from honey and sugars.
If you do want to purchase an organic Stevia product, you can always buy this:
If you are want to use a stevia extract for cooking purposes, here are the general guidelines to follow when you replace stevia for sugar:
1 cup of sugar = 1 tsp of powdered stevia extract
1 tablespoon of sugar = 1/4 teaspoon of powdered stevia extract
1 teaspoon of sugar = a pinch or 1/16 of a teaspoon of powdered stevia extract
Stevia is heat-stable to 392 degrees Fahrenheit, so that should cover just about any application in which you would use it. The only problem when you use stevia while baking is, regular sugar helps the backed goods rise. So please expect a different result when using stevia as a substitute.
Also note, if you are using stevia in your baked goods, the bulk of sugar you use needs to be replaced with something else. Maybe something moist like yogurt, applesauce or even a fruit puree. Or if you don't want to experiment too much at least replace half amount to the sugar used with the proper stevia measurements.
Tomorrow dangers on stevia. xxx