Just got back from a Liu Bao specialist. Found out that I did well!
This is the tea in question. Sorry, I forgot to shoot the brew itself. Very, very dark, almost black, with an easy-to-spot eun mu.
The expert said that it is at least 10 years old, but could be much older. The price I paid, he said, was a very, very good price.
He busted out two young Liu Baos for me to sample (5 yearsish). They tasted a lot like a young Shou Puerh. Deep, smooth flavors, but without that intricate and nuanced kick we love so much from aged sheng (or even some well-stored, aged shou). One had small leaves, and one big leaves. He explained that small leaves are more expensive and more sought after, though not necessarily better (like sheng is not exactly better than shou, just different, even though sheng ages to be more valuable). Both tasted great, but somewhat hollow at the end.
Then we tasted mine, and it had this flavor to it that I can only describe as tasting like snow, or rain, but with earthy, woody notes. This was why I bought it. It had a long and complicated aftertaste, as well as a deep, strong, bold flavor. He explained that this "rain-water-taste" is how he knows it is at least 10 years old, but could be much more. He said he doesn't know enough to say the outer range of how old it might be, but will have his teacher (the shop owner) taste a sample and get back to me (I doubt she will, but one can dream!).
Then we sampled a 1960 Liu Bao, and it was heavenly. Much smoother, seemingly from better quality leaves than mine. The leaves were big, and he explained that older Liu Baos didn't get divided into big and small leaves, and that mostly big-leaved Liu Baos are still around today. It was light and airy, super light-bodied but firm, with a flavor like where the water meets the root. (Side note: puerh comes from Camellia sinensis var. assamica, Liu Bao comes from Camellia sinensis var. sinensis, so the leaves are smaller, in general than puerh leaves.)
Finally, to sum up what I learned, he told me that we have to look for the aftertaste when determining age and quality, much like puerh, and to look for complex and intricate flavors. Same with the odor of the dry leaves. Also, that rain-water taste is an indication of good aging. He mentioned that older Liu Baos look different, and when he showed me a few what I noticed was an almost browner or seemingly dirtier color. He said the most important thing though is to feel the tea. Again, much like puerh, older teas produce a stronger "cha chi", or "tea energy". The young tea we drank felt like any other new tea in my body, generating energy and a feeling of calm, but the older ones gave me much more energy, more of a head rush. I drink a lot of puerh, and don't get "puer drunk" often anymore, but this hit me like I was brand new. I was walking down the street after feeling like bouncing, like I had too much (or just enough!) coffee. I can still feel the elevated energy now, about 2.5 hours later.
Sorry for such a long post, but I thought the tea chat folks interested in Liu Bao might enjoy the benefit of my experiences.
Thanks for reading!