There is a great deal of controversy about chaga's true ORAC value and the powders, extracts, and teas being sold containing this ingredient. In terms of the antioxidant content of chaga, the number can vary wildly.
Chaga is indigestible by humans in its unprocessed state and has virtually no antioxidant value. This is because humans lack the enzyme chitinase, which is necessary for digesting the chitin cell walls (which is where the bioactive compounds are found). To further complicate things, the antioxidant properties of the fungus can vary immensely based on the particular source and batch. That fact, along with product manufacturers using different processes and concentrations, has led to ORAC values purportedly ranging from 5,200 to 146,700 depending on the specific product and its manufacturer.
The brand with verified testing results proving ORAC value of 146,700 is impressive, however since 100 grams of their product costs $100 (as of April 2016) it is a high price to pay relative to the daily dosage or per capsule amount (333 chaga powder capsules = 100 grams).
Chaga (Inonotus obliquus) is a fungus which grows almost exclusively on the outside of birch trees in very cold climates. Technically, it is not a mushroom but rather the fungal mycelium. However, because they are almost exclusively called chaga mushrooms, we also refer to them as such to avoid confusion.
The chaga is a parasite of the birch trees it grows on, typically killing it around 20 years after the initial parasitism begins. While chaga mushrooms can be harvested from the outside of the tree rather easily, doing so doesn't stop the parasitic fungus from returning (as it is inside the tree) and therefore, the chaga will regrow in the same spot(s) they were removed and are known to reach their original size 3 to 10 years later.
As far as chaga mushroom health benefits and side effects, some manufacturers are making wild and substantiated claims about them. Some - though certainly not all product manufacturers - have made dangerous unsubstatiated claims alleging it is useful for cancer, diabetes, and cardiovascular disease. We encourage you to start your own research with Wikipedia's entry for "Inonotus obliquus" to help you decipher fact from fiction. That being said, for centuries it has been used in herbal medicine in Russia and other North-European countries.
As seen in the photo above, the fungus is mostly black because it produces large amounts of melanin. What do chaga mushrooms taste like? Well, surprisingly, almost like nothing - it has little to no taste. This is true whether it's hot or cold. Some say it has the slightest hint of a vanilla taste. Chaga tea is probably the most popular and oldest method of using this product. Chaga extract and powder have recently become popular.
The reason the ORAC value of 146,700 is referenced above is because it is the only report we have seen from Brunswick Laboratories for a chaga product or ingredient. That product manufacturer was Oriveda and the date of the report is June 2011.
We have not seen reports disclosed by other product manufacturers, instead they often reference "as tested by the USDA and Tufts University in Boston, MA." however chaga mushrooms were not in the previously published USDA ORAC data, nor have we found any substantiated evidence that the USDA and/or Tufts University ever produced such a report. If we are incorrect and such a report exists and can be validated, we encourage you to contact us and we will update this information.
Research Support, Non-U.S. Gov't: Brunswick Laboratories Test Report for Oriveda Chaga Extract Powder June 2011