One has taken the time to look closely at the production of a handful of balhyocha from different producers and have found that the basic production takes place in the following steps: withering, violent shaping/rolling, slow drying, drying.
Lets take a closer look...
After fresh tea leaves are picked they are left to wither in the sun. They are then left to wither in the shade usually for a considerable period of time. Some producers only let the tea wilt in the shade while others only wilt the tea in the sun. Most producers use a combination of sun wilting and shade wilting. The decision of how long or where to wither the leaves may have more to do with the weather of the day then a prescribed method. Instincts of the teamaster, their past production experience, and their connection to nature plays an important role in the making of balhyocha. This first step allows for the tea leaves to naturally oxidize, taking in deeply the mountain air as biochemical wonders start to transform the leaf.
The second step involves the withered leaves being rolled vigorously on a fibrous mat. Care is taken so that it is rolled vigorously but not torn or shredded. The shaping/rolling process here should strike a nice balance between the lighter shaping of green tea and the violent shredding of red tea. Proper pressure and technique here very much influence the final product. Here a more controlled prodedure is used to actively oxidize the leaf.
The third step involves the tea being left to slow dry on a heated floor in a warm room for a considerable amount of time. Koreans heat their homes using a system of heated floors call "ondol". This is the same system that is used to dry balhyocha. Nowadays ondol is almost exclusively electric but before such conveniences ondol was heated by firewood under the stone foundation of the house.
Some producers simply wait until the tea is completely dry from this method which usually takes a few days. Others may give it one last low temperature roast or considerably increase the heat in the room during the last few hours of drying.
Most times production of Balhyocha ends here but sometimes teamasters add their own special touches such as crushing the dried tea to induce more oxidization or storing the final product in onggi, the clay pots used to ferment kimchi, for a few months of fermenting before they bag the tea.
As you can see the final product has to do with the amount of withering time and the withering method, the amount of force and vigour used to shape/roll the tea, the temperature and amount of time used to dry the leaves, and the final touches.
You can also see that the use of Korean ondol heating and onggi storage makes this tea distinctly Korean.