Strange change of yield?

[Infinitee]

For months now SWIM been doing a lye/MHRB/Naptha extraction, using 1500ml Water, 80g lye 80g MHRB in 1/2 gallon glass jars. After extraction going to freeze precipitate over night (about 8-9 hours). First few yields were purely white. After a week or 2 yield slowly became pale beige and progressed to a light brown. Is there any reason for this? Extraction process hasn't changed at all but on one batch noticed some emulsion in the naptha layer (could that be some MHRB getting into the extractions?) Also, the extraction jars are never washed (because it is IMPOSSIBLE to scrape all of the product off of it since it is a round wide-mouthed jar)

Note: this yield also has a slightly different taste than the white crystals (not to mention fairly unpleasant). What is wrong!?

[*EDIT*] Also note: a hot water bath is not possible in SWIMs place of extraction. What are other options?

 

[E-Z]

Are you referring to the yield of each pull or each separate extraction? If the former that is normal. The final product usually starts to get darker since you're pulling more of the plant fats and other materials out. If its the ladder your guess is as good as mine. If you are using the exact same process as before the results shouldn't be any different. Perhaps your supplies need to be cleaned or are being stored wrong.