Studies show that ginseng improves memory, enhances libido and sexual performance, boosts immunity, and alleviates diabetes. But the very compounds that make it good for you also make it taste bitter.
Ginseng is found to contribute more to the bitter perception in energy drinks than caffeine, an indispensable component of these beverages and the very compound that sensory scientists use as their reference for bitter perception. Ginseng has over 30 bitter compounds. It is still unknown which compound or group of compounds is responsible for the bitter taste.

While experimenting with five possible solutions to ginseng’s bitterness problem, Soo-Yeun Lee and his team, University of Illinois, USA, discovered that cyclodextrins were able to capture the bitter flavor compounds through inclusion complexes and reduce bitterness by more than half. γ-cyclodextrins were found to be more successful than β-cyclodextrins and were more cost-effective.

These compounds have been used to mask bitterness before, but not at the level of ginseng used in a typical energy drink.
The U.S. energy drink industry is expected to reach $19.7 billion in sales by 2013, even though these beverages often have a medicinal taste because of their functional ingredients. The new findings might change this in the future.

• Sensory profile of a model energy drink with varying levels of functional ingredients-caffeine, ginseng, and taurine,
  L. C. Tamamoto, S. J. Schmidt, S.-Y. Lee,
  J. Food Sci. 2010, 75 (6), 272-278.
  DOI: 10.1111/j.1750-3841.2010.01655.x