Blue Strand in Tzitzit

A customer recently ordered a set of handspun tzitzit. Upon receiving the shipment, he was quite surprised to find all white tzitzit, with no blue strand.

He sent the following inquiry:

My tsitsit arrived today.  Is there a reason why blue strands were not included?

 I was tickled by the innocence of his question. He may have come across various "blue strand tzitzit" products offered by non-Jewish Internet dealers at very low prices, probably made of synthetic or plant dyes.

"Most Jews do not use techelet," I explained to him. The reason is quite complicated. Instead, the tzitzit are all white. If you go to our Tzitzit Strings page all of the items listed are all white, except for the last two." I sent him there so that he would see that the difference in price between standard all-white tzitzit and techelet tzitzit is very substantial.

But he was not satisfied, and again asked a very innocent sounding question:

But Moses commanded that we are to have a blue strand.  Is there a Talmudic explanation for deviating from this?

Tzitzit with blue strand, Rambam tying custom

In Talmudic times techelet was still used. But subsequently, during the turmoil under Roman rule, if I'm not mistaken, the correct source of the techelet dye was lost. Over the past century various efforts have been made to recover the lost dye. In recent decades there has been a brisk debate over the authenticity of the findings.

There is a whole lot of material available on the topic. For an initial overview, you might want to take a look at this page.

Ptil Tekhelet has some very convincing claims. In Israel, the ultra-Orthodox community tends to be very resistant to new changes. Techelet is seen more frequently within the more modern Orthodox community and in the U.S.