No Sack please

Just a guess, but "sack" was a term Shakespeare used for "sherry".

A "vow of no sack" in that sense would have implied abstinence.

Wasn't there a sherry called Dry Sack?

Sack, and Dry Sack.

The editors of the OED must have enjoyed their sherry, for this particular meaning of sack has one of the longest etymologies I've seen in the dictionary:

"Early 16th c. wyne seck+, ad. F. +vin sec+, 'dry wine'. Cf. G. +sekt+, earlier (17th c.) +sek+, Du. +sek+. +Vin sec+ is given by Sherwood 1632 (but not by Cotgrave 1611-32) as the Fr. equivalent of 'sacke'. According to Littré, +vin sec+ meant only 'dry wine' in the current Eng. sense, i.e. wine 'free from sweetness and fruity flavour'; there appears to be no ground for the assumption made in Grimm's +Deutsches Wörterbuch+, s.v. +Sekt+ (and in earlier German dictionaries from the 17th c. onwards), that it at some time meant 'wine from dried or partially dried grapes'. Some difficulty therefore arises from the fact that +sack+ in English, as well as +sekt+ in German, was often described as a sweet wine (so already in our earliest quot.), though Shakspere's mention of 'sack and sugar' shows that it was not always such even in the 16th c. It is possible that before the recorded history of the name begins it had already been extended from the 'dry' wines of a certain class to the whole class, and had afterwards come to be applied esp. to those wines of the class which were originally excluded. But evidence is wanting. The Sp. +vino seco+, It. +vino secco+, usually cited by etymologists, appear not to be recognized by the lexicographers of the respective langs. The form +sack+ is not a normal development from the original +seck+. It may perhaps be explained by the fact that in the 16th c. +seck+ was a provincial form of sack n.1; persons who were accustomed to regard 'seck' as a mispronunciation of +sack+ may have applied the supposed correction to the name of the wine. It is not, in the present state of the evidence, probable that there was ever any confusion with the OF. +vin de sac+ (' +Saccatum+, vin de buffet, vin de sac', in a gloss quoted by Godefr.), OHG. +sacwîn+ (written +saicwin+ ), MDu. +sacwijn, which according to early explanations meant a beverage made by steeping the lees of wine in water, and then straining through a bag."

From an article in the British Medical Journal, March 23, 1861. The author is agreeing with a Dr. Barclay that moderation is better than teetotalism. Given human proclivity to excess, a teetotaler will just find something else ot binge on.
>Who indeed sins more the laws of the gastronomic appetite, for example, than the veritable teetotaller himself? Barclay has well brought out this point. He who takes no sack for his drink is decidedly apt to eat a glutton's allowance of solids.

The Poet Laureate gets given a butt of sack (about 500 litres) when he takes on the job.

A headline in today's NYT:

"Umenyiora Looks Beyond Next Sack, Wondering What It All Means"

Thanks all. Much appreciated.

Simon Templar, The Saint in the Leslie Charteris novels and stories, used to drink Dry Sack.