It’s all in the weave.

Dear Word Detective:  When making concrete, one adds aggregate to create a stronger final product. Similarly, “grog” is added to clay to strengthen it. “Grog” is fired clay that’s been crushed into a powder. When added to clay, the resulting matrix is stronger than pure clay alone.    This meaning of “grog” is found all over the place, but I am unable to find any info on its derivation/etymology and am hoping you can help. So why is “grog” called “grog”? — Tom.

That’s a very interesting question, although that is not always a good thing. In many cases, I’ve found that the more interesting a question is, the harder it is to find an answer. In this case, I had begun to despair of coming up with a plausible answer, when I had one of those all-too-rare Eureka! moments when the fog lifted and I knew I had the probable answer. I had been presuming that the connection between “grog” the drink and “grog” in pottery-making, if it existed at all, was very tenuous. But it’s actually quite solid, if a bit roundabout.

We use “grog” today as a colloquial (usually jocular) term for any strong alcoholic drink (“The man was always on the grog, ‘n your Dad gave them the sack.” 1955), but “grog” began as the name for a very specific beverage. In 1740 Admiral Edward Vernon of the Royal Navy came to believe that the daily rum ration (of one-half pint) served to sailors was having a deleterious effect on his men. He issued an order that from that day forward each day’s rum ration was to be diluted with a quart of water (presumably to blunt the effect of the rum). The sailors under his command were, predictably, less than thrilled, especially because the drinking water aboard ship was famously foul. Vernon’s mixture must have seemed a waste of good rum.

Vernon’s sailors had, not surprisingly, already come up with a nickname for their commander, which was “Old Grog,” referring to the distinctive heavy “grogram” coat he wore on deck in heavy weather. (“Grogram” is a thick fabric made from wool combined with silk or mohair and often stiffened with gum.) So it made sense to call Vernon’s diluted mixture of rum and water “grog.” The term “grog” eventually percolated from Royal Navy slang into general usage, broadened to mean any alcoholic drink, and eventually gave us the adjective “groggy” to describe the state of being fuzzy-minded as if from drinking.

“Grog” as a term for fired and pulverized clay added to pottery to strengthen it has no direct connection to “grog” the drink. It does, however, have an apparent connection to Admiral Vernon’s “grogram” coat. The root of “grogram” is the French “gros grain,” meaning “coarse or large grain,” referring to the “pebbled” texture of the thick cloth. The hard particles of “grog” added to pottery clay strengthen the finished product and can, depending on the mixture, give the surface a slightly gritty texture that resists cracking. (Wikipedia claims that this effect in pottery and sculpture is called “tooth” and that the “grog” also speeds drying of the clay.) I’d be willing to bet that the coarse texture — “gros grain” — of the pottery “grog” accounts for the origin of the term.

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