Bog Butter, 1856

Extract from a paper presented to the Irish Natural History Society and later published in the Journal of that Society, on the General use of the potato in Ireland

MONDAY, MAY 26TH, 1856.


MR. W. R. WILDE (Sir William Wilde – father of Oscar Wilde) read a Paper on the introduction and, the time of the general use of the Potato in Ireland,- and its various failures since that period; with some notice of the substance called Bog-butter.

Bog Butter: by Sir William Wilde

“In enumerating the food of the Irish, Petty mentioned ‘butter made rancid by keeping in bogs ;’ and in the Irish Hudibras we read of-
Butter to eat with their hog,
Was seven years buried in a bog.’

When I originally read the statement of Petty, I came to the conclusion that he was wrong, and that this bog butter was much older than his time, but I have learned to correct that opinion. Why or wherefore the people put their butter in bogs I cannot tell, but it is a fact that great quantities of this substance have been found in the bogs, and that it has invariably assumed the physical and chemical characters presented by the specimen now before the Academy: It is converted into a hard, yellowish-white substance, like old Stilton cheese, and in taste resembling spermaceti; it is, in fact, changed into the animal substance denominated ‘adipocere’. Two questions arise, at what time the Irish ceased to bury butter, and how long it would take to produce this change in it.

From the’ Mechanics’ Magazine,’ for September, 1824, we learn that this substance, there styled ‘mineral tallow’ was first discovered in Finland in 1736. About the year 1820, a quantity of it, then called ‘mountain tallow,’ was discovered on the borders of Loch Fyne, in Scotland, and was described in the’ Edinburgh Philosophical Journal,’ vol. xi;

In 1817, a mass of this bog butter or tallow, weighing about 23 lbs., was discovered in a bog on the Galtee Mountains. In June, 1826, a tub, containing about 21lbs. weight of this substance, was found in a bog near Ballinasloe; it, was presented to the Royal Dublin Society by Lord Dunlo, and was described by Professor Edmund Davy in the Proceedings of that body. Since then, very many specimens of this substance have been found; we possess three or four very fine samples in the Museum of the Academy; and other collections, both public and private, contain several examples. It is almost always found in wood, either in vessels cut out of a single piece, like large ‘methers’, or in long firkins, of which there is a good example in the Museum. So far as I can gather, the bog butter is always found at a great depth, ten or twelve feet, at least, in old, solid bogs. Whether the vessels were originally buried at that depth; whether they were placed nearer the surface, and in lapse of years sunk; or whether the bogs havegrown over them, are questions I cannot determine.

How many years it would take to produce in tallow, suet, or butter, the remarkable change exhibited by all the specimens which have been discovered, is a question of much interest ; in connexion with which I may state the curious fact lately mentioned to me, that when the common fosses of Paris, into which a great number of bodies had been thrown in 1793, were opened a few years ago, it was found that the substance into which they had been converted was an ‘adipocere’ somewhat resembling this bog butter.

In the’ Edinburgh Philosophical Journal,’ to which I have alluded, will be found the first analysis of this substance that I am aware of. Professor E. Davy made a very careful examination of it in 1826, the results of which are published in the Proceedings of the Royal Dublin Society for that year ; I understand that a German, named Luck, published another analysis of it about ten years ago; and I have recently received the following communication from Mr. Sullivan, of the Museum of Irish Industry, who has paid much attention to the subject ; –
“I have obtained from every specimen which I examined more or less of all the peculiar oily acids of butter, which renders it more than probable that they were all originally butter. I may, however, observe, that the finding of these would not amount to absolute proof as to the substance being butter, as I have obtained butyric acid by the slow decomposition of flour under water; also from brain and meat, with fatty tissues attached; and we also know that all these acids can be produced by the oxidation of fats generally. One of the reasons which led me to think that they were originally butter is, that scarcely any of the other volatile acids of the series, produced by the oxidation of fats, besides those obtained directly from butter, are usually present in bog butter. I never detected the presence of salt in any of the specimens which I examined, at least not in any quantity to warrant the supposition that if it had been butter it was salted. In connexion with this result, which otherwise would be a great objection to the idea of its having been originally butter, it is well to bear in mind that butter is even now made in Cork and in the town of Antrim without salt.”

Two circumstances may have influenced those who buried this butter : it was done either for the purpose of security, or in order to produce that very change in it which Petty calls rancid. In Classin and Povelson’s ‘Travels in Iceland,’ we read that the peasantry and poor people eat in winter what is called sour butter, which is preserved without salt; and although it becomes in time acid, it may be preserved for more than twenty years. In former times there were public magazines attached to each bishop’s see, in which great quantities of this acid butter were stored up against years of scarcity; but we read, , when the sour butter is too old, it loses in its acidity and weight, dries up, and acquires a rancid taste.

The most remarkable reference to the substance under consideration, and one that serves to throw most light upon the subject, is that contained in Debe’s Description of the Faroe Isles in 1670; it is
there called (according to the English translation) preserved tallow and ‘Rue tallow ‘and was thus treated: the tallow, principally obtained from sheep, was cut in pieces, and allowed to rot awhile; it was then rendered, and cast into large pieces, which ‘they dig and put in moist earth to keep it, it growing the better the longer it is kept, and when it is old and is cut, it tasteth like old cheese. The most able peasants have ever much endeavoured to bring together a great quantity of that tallow, so that a countryman had sometimes in the tallow dike (that is, a place-in the earth where it is kept) above 100 loads, and this hath always been looked upon as the greatest riches of Feroe. For when sheep dye, such tallow is very necessary in the land, the longer it is kept being so much the better; and forreign pyrates having little desire to rob it from them. It may, therefore, not unreasonably be termed a hidden treasure, which rust doth not consume, nor thieves steal away.”

END of paper

NOTE: Since the foregoing was read to the Academy, I have received the following note from Mr. Curry on the subject :-
During my residence in London, in the summer of last year (1855), I fell in with a curious Irish poem of several stanzas, in the handwriting of the author, John O’Neachtan, an Irish scholar, well known in and about Dublin, between l710 and 1750.
The poem gives a vivid and most graphic description of a battle supposed to have been fought at Cross-bride, somewhere about Tallaght, in the county of Dublin, in the year 1740, between the farmer advocates of the potato, which had been nearly annihilated in the preceding year by the great frost, and the market gardeners and others, who gloried in the destruction of the foreign root, and gave a disinterested preference to the growth of the less prolific and more inaccessible edibles of barley, beans, peas, rye, cabbage, &c.
The part of this description which may prove of interest to you is that in which the writer always speaks of the potato as the white Spaniard, ‘Spaineach Geal’, that is, the white or generous-hearted Spaniard; and where he says that they gladdened the people’s hearts from the first day of August till Patrick’s day.