This is a farmer-style raw/sheng/green liu bao tea produced in 2009 by growers near Liu Bao township.
"Gan ku" means "bitteersweet" in Chinese, and as a young "farmer style" raw liu bao, this tea has punchy flavors. It's an educational example of what raw farmer style liu bao is like in its adolescence. Fans of sheng pu'er will recognize many this tea's flavors: dried hay, wood chips, and the namesake bittersweetness. You can also note its young age in the green colors of the leaves.
Storage is clean, with no moldy flavor or aroma. It was aged naturally in Liu Bao township until 2016, then in Wuzhou until 2019, then in Seattle, Washington. Liu Bao township and Wuzhou have a humid subtropical climate with an average relative humidity of 60-80%. Liu Bao is slightly more temperate than Wuzhou. It was not "wood warehoused".
What is "farmer style" liu bao?
Farmer style liu bao comes from a more traditional or old school process compared to how liu bao teas are typically created and graded today.
To understand farmer style liu bao, you need to know a little about how liu bao is produced and graded.
Liu bao tea is graded using a standard system, where "top grade" (特级) and "grade 1" (一级) include only bud tips. As grade numbers increase, leaves from farther down the bud stem are included. Grade 2 includes very little stem. Grade 3 includes larger leaves and tender stems. Grade 4 can include stems that aren't tender, i.e., small woody sticks. I have seen some labeled grade 5 and 7, where 7 was mostly mature leaves (called 黄片, huangpian, "yellow pieces", based on the color these leaves turn when dry, compared to the rich green of more tender bud leaves) and sticks.
Farmer style liu bao is produced with the entire bud stem and doesn't fall easily into the grading system, but averages about grade 3, with tender stems and large bud leaves, but few to no sticks or fully matured leaves. This is the household tea of small farmstead owners, often stored and aged in the family's own wood board sheds.
In addition, farmer style tea typically does not undergo wet piling, and is instead kept "raw" (生). Wet piling is the controlled fermentation process used to produce most factory liu bao teas nowadays, and is similar to the process for how "cooked" pu'er (aka shu pu'er, 熟普洱) is made.