The secret of the lost color

The blue thread that runs through Jewish history.

Murex trunculus straight out of the ocean (photo credit: STEPHEN EPSTEIN)
Murex trunculus straight out of the ocean
(photo credit: STEPHEN EPSTEIN)
Long ago, there was blue. A blue dye, obtained from a certain marine creature – a snail that lived off the Mediterranean coast. The dye was extracted from it by a specific process that was well known at the time. It was labor-intensive work. Fishermen would harvest the snails from the seabed, which was hard work because they were camouflaged with sand and slime. They would take their harvest to the dye houses located near the beach, where workers extracted the creatures’ digestive glands immediately, then crushed, salted, and steeped them in boiling water.
This yielded a green-yellow color, “like the color of leeks.” Only after the infused water was exposed to sunlight did the royal crimsons, purples and blues appear, according to scheduled timing.
The Talmud says that the blue color was as pure and beautiful as the sapphire Tablets of the Law. The Hebrew term for this royal blue is techelet. The name of the only snail good for making it is hilazon.
In the ancient world, fabrics dyed with these colors were literally worth their weight in gold. The nobility of ancient Egypt, Rome and Greece wore them not only for their beauty but to flaunt their prestige. In Judaism, the robe of the high priest was dyed techelet blue. It’s said that Mordecai of the Purim story dressed in blue-and-white robes after he became chief vizier to Ahasuerus. Yet the common man also bought fabric dyed blue with techelet, usually only a few woolen threads. These blue threads, knotted together with those of common white wool, were drawn through the corners of the tzitzit garment, making the ritual fringes worn every day, as commanded by God to Moses.
The blue thread among the white was a reminder: “You shall look upon it and remember all the commandments of the Lord, and do them; and that you go not about after your own heart and your own eyes, which you use to go astray; that you may remember and do all My commandments, and be holy unto your God.” The sage Rabbi Meir (second century) would say that wearing the thread of techelet is considered as great as if a man greeted the Divine Presence, “For techelet resembles the sea, and the sea resembles the sky, and the sky resembles God’s holy throne.”
When the Romans conquered Israel, they passed sumptuary laws restricting clothing of those luxurious colors to the nobility. Jews were forbidden to wear blue or make the dye. But so precious was the mitzva of wearing techelet that some Jews risked the severity of Roman law to manufacture the dye in secret and smuggle blue threads to other communities around the land. With the Arab conquest of Israel in 639 CE, the techniques of identifying the snails and extracting the dye were lost. Jews never abandoned the tzitzit garment, but all its fringes were white.
Yet the blue thread continued to run through Judaism, in holy books and debates in the houses of study. The source for the blue dye was known to come from the hilazon snail, but no one knew how to identify the creature for sure, nor even how to harvest it. How to extract the sky-blue color from the snail remained a secret. For over 1,400 years, techelet remained a mysterious echo from the past – one of many sacred things lost in the exile from the Land of Israel and the dispersion of Jews throughout the world.
In addition, some rabbis considered that after so many centuries without techelet, it wouldn’t be permissible to try making it again, supposing the hilazon was rediscovered. Wouldn’t it be better, they argued, to wait until Messianic times to revive the custom? For then the hilazon would be identified without question. The techelet issue continued to serve as a subject for study and discussion, but no one expected to see the real thing in their lifetimes.
But there are always second and third opinions in Judaism. Maintaining that the techelet could and should be used again, one rabbi eventually undertook to rediscover it. In Poland, in 1889, a hassidic sage became convinced that the cuttlefish’s ink was the source of techelet. This was Rabbi Gershon Henoch Leiner, the Radziner rebbe. He traveled to Italy to continue his research, working with a local chemist. The chemist used iron filings and chemicals to produce Prussian blue; the cuttlefish, although present in the mix, did nothing to produce the desired color. Still, the Radziner rebbe was convinced that the mystery was solved. He had thousands of tzitzit sets made with the blue thread, and his hassidim began to wearing them.
This gave rise to a new debate. Most Jews rejected the “new techelet,” today considered a fraud of the Italian chemist. But the Radziner system of making blue dye survives until today, and thousands of Radziner Hassidim wear a blue thread from it in their tzitziot.
Blue color can be extracted from plants, specifically indigo and woad. Techelet and indigo can’t be told apart by the ordinary observer; even their molecular composition is the same. But indigo and woad must be discounted as a legitimate source of blue for ritual purposes, because it’s known that techelet came from a sea creature that thrived off the northern coast of Israel. In addition, these plant dyes rub off and fade with washing, while true techelet’s color, according to the talmudic description, is stable even under stress testing.
In 1913, Rabbi Isaac Herzog, then chief rabbi of Ireland and later to be chief rabbi of Israel, was working on his doctoral thesis; it concerned the study of blue in Jewish law. Herzog even invented a word for it: porphyrology, or the study of purple. Having the Radziner blue color professionally analyzed, he understood that it was the result of an inorganic chemical process not connected to the presence (or absence) of the cuttlefish. A French zoologist had experimented with extracting blue color from the marine snail Murex trunculus. Herzog became aware of these experiments in his investigations and continued on the track of Murex. His own experiments yielded a deep purple color, but not the sky-blue described in the Bible. And there matters stood another 60 years.
Oddly enough, it was Herzog, having debunked the Radziner system, who allowed it to revive after World War II. Along with almost all Jewish property in Poland, the Radziner techelet factories had been destroyed. Herzog allowed surviving Radziner Hassidim to examine his old correspondence with the factories’ owners. From those letters, they reconstructed the system of producing the blue dye that Radziner Hassidim still use.
The techelet was rediscovered with certainty in the early 1980s. Prof. Otto Elsner of Shenkar College of Engineering and Design, conducting experiments with Murex trunculus, saw that the dye extracted from the snail changed from purple to deep blue – only when exposed to the sun. At last, the mystery of the techelet was solved. If there’s one thing never lacking in the Mediterranean, it’s sunshine. Certainly, the ancient techelet manufacturers knew to let the dye stand in the sun, watching its colors transforming from yellow to crimson and purple to pure blue.
In 1985, Rabbi Eliyahu Tavger of Jerusalem pioneered the method used today to extract techelet from the Murex trunculus snail. To educate Jews about techelet and make blue tzitzit threads available to everyone, volunteers formed the nonprofit P’til Tekhelet Foundation in 1989. Today, shops associated with the foundation sell about 1,000 sets of tziziot with techelet every month. According to Rabbi Mois Navon of the foundation, it’s mostly the national-religious community that uses the techelet, although there’s growing support among haredim.
The P’til Tekhelet factory is located in Kfar Adumim. When I asked why it’s located so far from the sea, Navon explained that a law protecting the Murex trunculus snail forbids removing it from the coast. However, the snail lives all around the Mediterranean coast. Much of the factory’s raw material is imported from Croatia, where fishermen harvest it for sale to local restaurants. There have been several attempts to breed the snail locally in tanks or pools, but it’s an expensive procedure and hasn’t yielded any great amount of dye.
Navon explained the rediscovered procedure using modern methods. Baking soda must be added to boiling water to break down the enzyme present in the snail’s digestive gland. (Presumably the ancients used a form of potassium, or wood ash.) Added sodium dithionite makes the dye water-soluble and improves the quality of the color. Finally, citric acid must be added to the vat to neutralize the basic solution, which otherwise would cause the wool dyed in it to dry and crumble.
Individuals and groups may tour the Kfar Adumim factory and see how techelet is made by hand, from the shearing of the sheep to the spinning and dyeing of the woolen thread. Visitors may also join interactive tours that run all summer on the beach. You can snorkel in search of the hilazon yourself. The beach tours are a huge hit with kids.
The P’til Tekhelet Foundation also sends lecturers to schools and clubs, and many quotes on its website testify to its success. Schoolchildren can make their own techelet with a kit from the foundation containing materials and instructions. It’s “a unique multidisciplinary presentation suitable for the classroom. Hands-on dyeing demonstrations and detailed explanations highlight the interplay of science and Torah through chemistry, biology and Talmudic sources.”
The Maggid of Kovno said, “Techelet is a harbinger of the Messiah.” ’Tis a consummation devoutly to be wished. 
To learn more about the P’til Tekhelet Foundation: (02) 590-0577, and