Shellfish History

On R-Month Oysters

The taboo against non-R month oysters dates back to Ancient Rome, and Cicero was one of the first to explore it.

By John Lomax September 12, 2013

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A prime Texas oyster.

So I stumbled upon the following notice in the September 22, 1838 edition of the Telegraph and Texas Register, the Houston-based broadsheet that was then the paper of record for the Republic of Texas.

"You must be fined," said the alderman, "for selling oysters in a month that has no R in it."  "Please your honor," replied the oysterman. "I spell it OR, OR-G-U-S-T. August." The man was excused. 

Cornpone humor aside, it set me to wondering about the origins of the R Rule. Little did I know I had just punched my ticket to Ancient Rome.

Houstonia former food editor Robb Walsh, author of Sex, Death and Oysters: A Half-Shell Lover's World Tour, says that the R Rule is very flawed here in subtropical Houston, as a few of our R months feature subprime and potentially lethal bivalves.

Thanks to the vibrio bacterium, which thrives in the 90-degree bathwater that's out there now, Texas oysters are more dangerous in September than just about any other month. As the water temperature falls below 65 degrees, the vibrio slinks away to wherever vibrio go when it's too cold. Meanwhile, the oysters start accumulating tasty glycogen to insulate themselves from the cold. The more of that juicy, sweet opaque glycogen, the fatter and tastier the oyster. Walsh says that his rule of thumb for prime half-shell enjoyment in these parts is between Christmas and Easter. 

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Now that's what we're talkin' 'bout.

"Summer oysters are like winter tomatoes," Walsh said. "If you are absolutely dying for one, fine, go ahead, but don't expect much." 

The taboo goes all the way back to Roman times, and no less an authority than Cicero became obsessed with the R Month Taboo, and even went do far as to pen De Ostreis, a heavily-researched treatise on the subject.

Cicero wondered why the taboo had been in place for the 400 years preceding his birth in 106 BC, when at one time the Roman lower classes slurped oysters safely all the year round. His investigation turned up the following conclusions, nicely summarized by Michael C. Hild (who in turn summarized a 19th century New York Times article).

Take it away, Inspector Cicero...


Cicero goes Columbo on the R Month Mystery.

  • Wealthy Romans retired to the beach during the summer months, while the masses stayed home.
  • Seeking volume sales afforded by the hordes of Roman unwashed in the big city, coastal oystermen sent the best of their haul to town. The elites were served the scraps, which were often "unwholesome," to put it delicately. 

    Awful oysters. Imagine them with sulphate of copper too.

  • To make matters worse, these coastal oystermen liked to try to conceal the rancid tang of these nasty oysters with sulphate of copper, "a most objectionable condiment."
  • Lots of elites got sick. 
  • Therefore, they decreed that R-month oysters should be banned for all, and they were, for everybody in every province of the Empire. 

Thank you Inspector Cicero, you are dismissed...

Roman law then prevailed over much of Europe, and even though water temperatures were quite different in the Roman province of Britannia than they were in the Mediterranean, Britons became just as fearful of non-R month oysters as Spaniards and Romans.

In the millennia since, it became an across-the-board taboo in Western culture and jumped the Atlantic with the Europeans. Some states have adopted laws against the consumption of non-R months oysters, as we saw in the corny example that sent me tumbling me into this rotten oyster-strewn Roman rabbithole.

In the end it appears, the Romans did was enact a universal solution to their own provincial problem.

Roman oysters probably were not totally safe in the warmest of the non-R months, as they have a fairly balmy climate by European standards. However, as evidenced by the masses of working folk who ate them year-round with little or no ill-effect, the vast bulk of the dangers came most likely from the rancid refuse the elites were being served at the beach rather than vibrio or some other oyster-borne bacterium. 

What's more, Walsh points out that it's peak oyster season from Cape Cod north to the Canadian Maritimes right now. The water is already below 65, and the oysters are getting plump. On the other hand, by the time January rolls around, many of the best oyster beds in the Great White North will be encased in ice, and the oysters will be withering away inside their shells. 

So some regions only get a couple of prime R months right at the end of summer and beginning of fall, and others, like us, should wait out the first three of the R Months and some of April. 

Unless you want cooked oysters, which are always safe, and as Walsh points out, always delicious when charred at Gilhooley's.

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