Questions on Tekhelet Decomposition Process

Questions on Tekhelet Decomposition Process

Questions on Tekhelet Decomposition Process 150 150 Israel Ziderman

Date: May 21, 2020

Email correspondence between Dr. Israel Ziderman and Rafi Hecht.

You mentioned before that Ptil and co. strip the monobromoindigotin dyestuff into indigotin, which you feel makes it kala ilan.

Questions:
1. Does that mean that in Menachot 42b, Shmuel bar R’ Yehuda was wrong in adding Sammemim? If not, what would be added if all that’s needed is sunlight?
2. If Tekhelet is not supposed to be the same molecular structure as Kala Ilan, how else do we understand the Gemara’s analysis of “Ani Hashem Elokeichem” who knows the difference between what the two are?
P.S. thank you for taking the time and having the patience to answer my questions 🙂
Response

You mentioned before that Ptil and co. strip the monobromoindigotin dyestuff into indigotin, which you feel makes it kala ilan.

  • It is not Kala Ilan: it is the same indigotin molecule as Kala Ilan.

Questions:

  1. Does that mean that in Menachot 42b, Shmuel bar R’ Yehuda was wrong in adding Sammemim? If not, what would be added if all that’s needed is sunlight?
  • Biochemically, for the dyestuff formation, sunlight is needed for argaman, but not for trunculus: sunlight could perhaps even spoil the shade/dyestuff obtained.
  •  In both dyestuffs, an insoluble solid is formed.
  • After this dyestuff-formation from the hilazon, there comes the actual dyeing process, which was carried out by bacteria in the presence of added alkali (samamanim): the dye dissolves so as then to be absorbed and dyed into the wool when immersed into the vat (Hebrew יורה  YORA(. This is called today a vat-dyeing.
  • For details of sammamanim, see Tosfot on Menahot 42b!
  1. If Tekhelet is not supposed to be the same molecular structure as Kala Ilan, how else do we understand the Gemara’s analysis of “Ani Hashem Elokeichem” who knows the difference between what the two are?
  • The gemara Menachot 42b-43a and Rambam Tzitzit 2:5 detail their diagnostic chemical test-procedure to distinguish between tekhelet and kala ilan. This would be fortuitous If they had the same molecular structure!
  • The test itself does not specify quantities, so it couldn’t be unequivocal.
  • The test is based upon comparison of the different behavior of two dyed wool samples, one of genuine tekhelet and the other claimed to be genuine. Without an authenticated sample to be used in the test, it may not convince the mumcheh nor the customer wishing to purchase tekhelet.
  • Did  the Ancients really bother to waste centuries and millennia promoting a tekhelet/hyacinthine purple industry and commodity worth its weight in gold, while they were at the same time using the very same merchandise, made from the inexpensive and widely used plants indigo, isatis and woad? If not, then tekhelet is not indigotin/isatis/woad!

Does that answer your enquiry? I’m not sure I fully understand your reference to Hashem: at least, I believe He will accept my argument…

Israel Ziderman

Scientific Director, Tekhelet Foundation
Chairman, Union of Civilian Research Scientists in Israel
Scientific Editor, Yalkut Journal of the Israel Textile & Fashion Association

All stories by : Israel Ziderman