===ETHP===
ETHP/ETPY (2-ethyl tetrahydropyridine(abbreviated: ETHP or ETPY) was first identified in wine in 1973, but until recently further studies weren't able to confirm its presence in wine. Its odor threshold is quite high (see [[Tetrahydropyridine#Thresholds_and_Quantities_Found_in_Mousy_Wine|Thresholds]]), and so it was not considered a major source of mousy off-flavors in wine for some time. Consequently, research on ETHP has been limited. More recently, it was shown that Lactic Acid Bacteria (LAB) can produce above threshold levels of ETHP, making it recently important to wine researchers <ref name="Snowdon"></ref>.
It has been speculated by scientists studying mousy off-flavors in wine that its production is the result of slow metabolism of ATHP into ETHP by ''Brettanomyces''. ETHP was observed to form much slower than ATHP and coincided with a decrease in ATHP. This slow production of ETHP may be another reason it has been underestimated by researchers until recently <ref name="Snowdon"></ref>. It is not known whether or not ETHP can degrade into another byproduct.