Hello Bruce and all,
Remember though, Bruce, that an NSA statement of one country does not necessarily pertain to all countries, nor is any interpretation they make infallible--only their decision is binding (on the believers in that country). And of course, the letter would be helpful to have too. Here are some authoritative quotations on the topic:
"Under no circumstances should Bahá'ís drink. It is so unambiguously forbidden in the Tablets of Bahá'u'lláh that there is no excuse for them even touching it in the form of a toast, or in a burning plum pudding; in fact, in any way."
(From a letter written on behalf of the Guardian to an individual believer, March 3, 1957: Cited in a letter from the Universal House of Justice to the National Spiritual Assembly of Ecuador, December 21, 1972, in Lights of Guidance, no. 1173)
"You ask whether it is permissible for the friends to use cake flavours, such as vanilla, lemon and rum flavoured extracts, as such flavours have a certain percentage of alcohol in them, and whether Bahá'ís may work in factories manufacturing such extracts.
"We have found no texts prohibiting the friends from using flavoured extracts in their food. This may be a matter for later legislation by the Universal House of Justice but for the time being the friends should be left free to do as they choose. The same principle applies to those who are employed in factories manufacturing such extracts."
(From a letter of the Universal House of Justice to an individual believer, April 7, 1974, in Lights of Guidance, no. 1174)
"With reference to your question whether those foods which have been flavoured with alcoholic liquors such as brandy, rum, etc., should be classified under the same category as the intoxicating drinks, and consequently be avoided by believers, the Guardian wishes all the friends to know that such foods, or beverages, are strictly prohibited."
(From a letter written on behalf of the Guardian to an individual believer, January 9, 1939, in Lights of Guidance, no. 1175)
Another interesting quote to me (which seems it might discourage artificial additives as well!) is this one:
If alcohol were beneficial, it would have been brought into the world by the divine creation and not by the effort of man. Whatever is beneficial for man existeth in creation.
(From a Tablet of Abdu'l-Bahá to an individual believer, translated from the Persian: Prohibition of Intoxicating Drinks, A Compilation, April 1979, in Lights of Guidance, no. 1171)
Of course this might be a case of "exaggerated emphasis", because alcohol does occur "naturally" in the form of overripe fruit (and even "artificial" creation is not of course creating any entirely new components that didn't already exist in some form). One might argue, however, that 'Abdu'l-Baha's intent of "natural" is that something is readily provided to us and abundant in its normal state (though some things are harder to prepare than aging fruit, and yet there is no dispute about them). And again, we have to take into account degree, and perhaps as you suggested Bruce, intent.
It's a little puzzling to me also that the House states "We have found no texts prohibiting the friends from using flavoured extracts in their food" (the context includes "rum flavoured" ones) yet the next quotation cited states "foods which have been flavoured with alcoholic liquors...should be...avoided by believers". The statement "we have found no texts..." implies, however, that texts can exist, so maybe the second quotation was simply not uncovered at the time and overrules the first. (The only other difference between the two that I can see is that the first one is about adding an extract to the food, while the other is about having food which is already flavored--a difference which should hardly make any difference, I would think. Moreover, if you're using a flavoring with alcohol, you're adding something "unnatural" and using a product where someone had the "intent" to add alcohol to the flavoring; if there is a difference, the only one I can see is marketing, and even there, that would seem to preclude "rum flavoured" ones...)