Natural or Synthetic Techelet

B”H

Can we use synthetic techelet?

From one of my Rabbis a great teacher:

A Breslover

Introduction:

The mitzvah of techelet, or the blue thread in tzitzit, has a profound history and intricate halachic debate. Commanded in the Torah, it symbolizes divine connection and holiness. The cessation of techelet production due to Roman decrees in the third century, combined with challenges in identifying the chilazon, the sea creature thought to produce this dye, has led to centuries of controversy.

Today, we see renewed interest, with differing opinions on how to fulfill this mitzvah. This overview explores historical sources, rabbinic perspectives, and modern research, shedding light on the varied approaches toward reviving the mitzvah of techelet.

The Tosefta rules that “if not from the chilazon, it is invalid,” though many assume the Gemara concurs, which is not definitively clear. Below is my perspective on the Techelet controversy.

The Torah commands us to include a “cord of blue” in our tzitzit, which was faithfully observed until the third century, when the Roman/Byzantine authorities decreed that only royalty could wear blue. They shut down the blue-dye production centers, mainly located in northern Israel and Lebanon. The Talmud rules that when techelet (the blue dye) is unavailable, the tzitzit can still be worn with white strings only.

It’s important to recall that no synthetic dyes existed until the 18th century. The Talmud disallows indigo (kala ilan) but does not provide an explicit reason. The Tosefta, however, specifies that any dye not derived from the chilazon is invalid, a view most rabbis upheld. Some argue, however, that the Talmud mentions this only as a custom, not a strict ruling. Rabbi Israel Ariel, head of the Temple Institute, supports using any long-lasting blue dye as valid for techelet, echoing Maimonides’ similar ruling regarding the sanctuary, where techelet is also required.

Over the years, various rabbis and groups have tried to revive techelet. The first was Rabbi Gershon Henoch Leiner, the Radziner Rebbe, in the late 1800s. He sought a sea creature fitting the cryptic descriptions in sources and found the cuttlefish in an Italian aquarium. Although its natural dye, sepia, is brown, a chemist turned it blue through a test for nitrogen. However, this reaction would produce blue with any nitrogen source, even unrelated substances. Rabbi Menachem Burstein, a leading authority on techelet, once mentioned to me that, improbable as the cuttlefish may seem as the chilazon, it does appear to fit Maimonides’ view. Today, Radziner and many Breslover Chassidim use this techelet.

Archaeological finds reveal ancient dye factories filled with thousands of snail shells from multiple species, raising the question: Which of these (or combination) is the Biblical chilazon? The “Ptil Techelet” group identified one species, whose dye is chemically identical to indigo, potentially explaining the Talmud’s prohibition on plant-based indigo. Many rabbis accept this identification, though I personally question the production method. Another researcher, Dr. Shaul Kaplan—the only Orthodox oceanographer I know—advocates for a different species that naturally produces blue dye without oxidation. Despite its strengths, his view remains less accepted.

Most rabbis refrain from endorsing any specific candidate for one of several reasons. First, the exact identification of the chilazon or the precise shade of techelet remains uncertain. Many assume a sky-blue shade, while Rashi describes a greenish blue and Rambam a near-black dark blue. Some hesitate due to the Ari’s statement that techelet will only return with the Messiah, although Rabbi Naftali Katz, a great kabbalist, suggested that rediscovering techelet would signal the coming redemption. Others feel that if the greatest rabbis over the past 1,600 years didn’t have it, who are we to reintroduce it? It’s known that the Radziner Rebbe gifted the Chafetz Chaim a set of techelet, which he reserved for Rosh Chodesh.

There’s also debate over how many tzitzit strings must be blue. Tzitzit consist of four strings, folded to create eight. Rambam holds that only one of the eight should be blue, Raavad that one complete string (two of the eight) should be blue, and Rosh that two of the four, or four of the eight, should be blue.

Each position has modern advocates.

For myself, I use Radziner techelet when I can obtain it. Otherwise, I follow Rabbi Ariel’s view, using an artificial blue dye. May Hashem guide us on the straight path and renew our days as of old.

Conclusion:

In conclusion, the reintroduction of techelet brings both promise and challenge. From Rabbi Ariel’s acceptance of durable blue dye to the Ptil Techelet movement’s archaeological findings, the effort to reconnect with techeletsignifies a longing for authenticity and tradition. While halachic debates continue over the color, source, and number of blue strings, these discussions enrich our understanding of the mitzvah and its symbolism. Ultimately, whether through historical dyes or modern alternatives, the commitment to wearing techeletreflects a desire for spiritual closeness and a hope for redemption, as we pray for Hashem to renew our days as of old.

Shtiebel on the Hill follows suit if we can not obtain Radziner Techelet we use artificial dye…