I thought this new research might sparks general interest in the forum.
https://www.sciencedirect.com/science/a ... 3824006467
Effect of storage time on aroma profiles of wuyi rock tea
" It is noteworthy that the content of aldehydes slowly increased as the storage time increased. Elevated aldehyde levels add a fatty note to tea (Q. Dai, Jin, et al., 2020), which indicates that WRT storage must be halted before aldehydes compromise product quality."
Interesting. So they suggest that there might be optimal storage time, and tea should be capped at that due to aldehyde levels and "fatty" notes. I do wonder about that, I'm not quite sure what taste they mean. Old oolongs that I've been less-happy about have been either stale (i.e. tasteless) or sour, or both. Of course these article is looking at quite short storages.
"It is worth noting that the storage of WRT resulted in the production of increased number of odor-active volatiles (OAVs >1), which seemingly augmented the aroma of WRT. "
So storage (at least within the scope discussed) increases volatiles and intensifies aromatics.
Earlier:
"These volatiles were categorized into four groups, and different trends were observed among the groups. In group 1, the volatile concentration increased after 8 weeks, reaching its peak after 16 weeks of storage. Volatile concentrations in group 2 suddenly increased after storage for only 2 weeks and remained at high through the following storage periods. In group 3, volatile concentrations rapidly increased after 4 weeks, which then swiftly declined. The concentrations of volatile in group 4 were generally high before storage but decreased after storage. "
Interesting again. There is no discussion on whether this groupings have any taste characteristics, it seems like their main interest here was possibly recognising a chemical fingerprint for different storage times.
Their fig 1. shows sensory analysis on the taste:
"The results showed that WRT without storage (CK) had strong roasted, burnt, and nutty odors; moderate woody and coffee/cocoa-like odors; and faint floral and fruity odors. The WRT stored for 16 weeks had strong floral and fruit odors; moderate woody, roasted, and coffee/cocoa-like odors; and faintly nutty and burnt odors. The floral and fruit odors increased with an increase in the storage time, whereas the roasted, burnt, nutty, woody, and coffee/cocoa-like odors decreased."
It's a pity that they didn't try storage for longer, it would have been interesting to see when fruity/floral -caps and starts to decrease, though that might take quite a while.
Interesting. So they suggest that there might be optimal storage time, and tea should be capped at that due to aldehyde levels and "fatty" notes. I do wonder about that, I'm not quite sure what taste they mean. Old oolongs that I've been less-happy about have been either stale (i.e. tasteless) or sour, or both. Of course these article is looking at quite short storages.
"It is worth noting that the storage of WRT resulted in the production of increased number of odor-active volatiles (OAVs >1), which seemingly augmented the aroma of WRT. "
So storage (at least within the scope discussed) increases volatiles and intensifies aromatics.
Earlier:
"These volatiles were categorized into four groups, and different trends were observed among the groups. In group 1, the volatile concentration increased after 8 weeks, reaching its peak after 16 weeks of storage. Volatile concentrations in group 2 suddenly increased after storage for only 2 weeks and remained at high through the following storage periods. In group 3, volatile concentrations rapidly increased after 4 weeks, which then swiftly declined. The concentrations of volatile in group 4 were generally high before storage but decreased after storage. "
Interesting again. There is no discussion on whether this groupings have any taste characteristics, it seems like their main interest here was possibly recognising a chemical fingerprint for different storage times.
Their fig 1. shows sensory analysis on the taste:
"The results showed that WRT without storage (CK) had strong roasted, burnt, and nutty odors; moderate woody and coffee/cocoa-like odors; and faint floral and fruity odors. The WRT stored for 16 weeks had strong floral and fruit odors; moderate woody, roasted, and coffee/cocoa-like odors; and faintly nutty and burnt odors. The floral and fruit odors increased with an increase in the storage time, whereas the roasted, burnt, nutty, woody, and coffee/cocoa-like odors decreased."
It's a pity that they didn't try storage for longer, it would have been interesting to see when fruity/floral -caps and starts to decrease, though that might take quite a while.
