I was kind of flabbergasted.
I know a Judaica dealer in downtown Jerusalem who’s not observant (yet). I asked him where he gets his 7 cm mezuzah scrolls. The 7 cm mezuzah is hard to procure; it’s quite small and most sofrim (scribes) are not trained to write that small. “Yehuda writes all of these parchments for me,” he explains. “A rabbi in Philadelphia told me to only buy from Yehuda.”
I took a look at the caliber of the writing. Not very impressive. Obviously he churns out a lot of mezuzahs at a low price. I asked the dealer how much he pays for them, and indeed it was quite a low price. I started to wonder whether these mezuzah parchments are reliably kosher.
That’s bad news. I’d be willing to bet this dealer is selling a significant number of non-kosher mezuzah scrolls to people every year.
To ensure a mezuzah scroll is kosher, the checking process may be more important than the writing process.
There are different kinds of sofrim out there. Some take their time and write gorgeous mezuzahs. Others work fast and sell them to dealers at low prices, and the dealers — hopefully — then sell them to consumers at affordable prices. Although the high-end sofrim make much fewer mistakes that would render a mezuzah non-kosher, even they make mistakes.
I once saw a very conscientious sofer come back from asking his rav about a mezuzah he had spent a lot of time writing. Looking quite glum, he took out a pair of scissors and cut a big gash in the mezuzah. It was posul (non-kosher) and he didn’t want it to somehow wind up on someone’s doorpost. What was wrong with it? There was a reish that looked too close to a dalet.
How are mezuzah scrolls checked? Nowadays usually you run them through a computer scan using a program that can identify the letters. The software skims through the text to make sure there are no extra letters or missing letters. In other words, it’s looking for typos. This type of check is very common today, but is not mandated by halacha, obviously.
Then there is a manual check by a qualified mezuzah checker, known as a magihah. His job, for the most part, is to make sure all of the letters are properly formed (i.e. that the reishes don’t look like dalets, that the yuds aren’t so long that they start to look like a vav, etc.), to make sure the spacing is correct and to make sure none of the letters are touching. This is critical, because a very small mistake that can be easily overlooked could render the mezuzah non-kosher. Some dealers even check manually twice.