Cracking the code of the modern matzah
Until the Middle Ages when it became skinny, matzah was an altogether doughier snack
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The Aviv bakery in Bnei Brak, Israel, produces matzot using computers
While many dishes go in and out of fashion, matzah has made it on to our Passover menus year-in-year-out, ever since the Bible instructed us to eat it.
Rabbinic texts such as the Mishnah and the Talmud rarely venture in to the territory of cookbooks, but for matzah they make an exception. Their redactors spilled much ink laying out the recipe and broad technique for production.
But despite the long and proud heritage, the matzah we eat today actually differs significantly from the matzah of old. It is still made according to rabbinic insistence that matzah is "fast food," made in less than 18 minutes, and it still uses the old recipe of water and flour that has been left to rest overnight.
But even the flour used has seemingly changed over the years. Most matzah today is made from standard wheat flour. But until the Romans conquered and brought an "agricultural revolution" to the Land of Israel "there was not a lot of wheat," says New York culinary historian Kenneth Ovitz, author of The History of Seders.
Ancient matzah was more like pitta or naan
This has led him and other experts to the conclusion that until some point in late antiquity, matzah was made with spelt flour. His research also suggests that matzot were crunchy, and tasted like cornbread or corn muffins.
Over the centuries the matzah has gone through many other changes, for better and for worse. It has lost weight, lost its good looks, and become tastier.
The original rules regarding matzah were relatively lenient. Within the 18 minute time-limit it is possible to make something doughier than today's matzah - something akin to pitta or naan bread, which is what was most likely used during Temple times when families feasted on a Paschal Lamb.
One clue we have to indicate that matzot were thicker and therefore softer is that earliest works of Jewish law instruct people to keep them thinner than the size of a closed fist.
But matzot steadily slimmed. Already in the era of the Mishnah - which was codified in the early third century - there were moves to limit the size to the thickness of one finger. The concern was that the thicker the matzah, the greater the danger of dough remaining uncooked and therefore being classed as chametz.
The trend has continued in the last century. Today you will get six or seven matzot to the inch. But the Jewish Encyclopaedia of 1906 reported: "In modern times the matzah is much thinner, varying from four to five matzot to the inch."
A related change is that matzot became harder over the years, with the exception of certain Sephardic communities which even today eat soft, pitta-like matzot. This was both because people used thinner dough and because - also in the era of the Mishnah and some say earlier - people started perforating the dough before baking. The holes were another measure to prevent chametz forming by stopping the dough from swelling.
But the holes were not punched in straight lines like in today's matzot - back then the holes in your matzah often formed intricate artistic designs. Eventually it was banned out of fear that if laymen crafted designs it would take them too long and the matzah would become chametz.
The worry of matzah-baking taking too long has almost become a thing of the past thanks to an innovation that was initially opposed by many rabbis (and is still shunned by some) - the matzah-baking machine, invented in the late 19th century.
"The whole process today takes three to four minutes," says Roy Wolf, who runs Aviv Matzah, the largest matzah baker outside the US.
There are other differences between early machine-baked matzot and those eaten today. They were invariably round, not square - the change in shape came about because squares are quicker to prepare.
Taste-wise, says Mr Wolf's grandmother Sarah Wolf, who founded the company 65 years ago and still works at the factory every day, "the flavour now is better than ever - computerised control means that there is much more uniformity than there was."