In Jamaica, the materials used in the wash are (1) molasses; (2) skimmings which accumulate during the purification of the sugar, and are allowed to "sour" during storage; and (3) "dunder," viz., the residue remaining in the still after the distillation of the rum. These ingredients with water form the wash, which is fermented, and then distilled in a pot-still.

The slow fermentation allows of the development of bacteria] action, in addition to the alcoholic fermentation produced by the yeasts, and this appears to be an essential feature of the manufacture of Jamaica rum. This is especially the case in the production of 'flavoured' or "German" rum, which, as a result of special fermentation, contains a higher proportion of esters and other secondary products than are found in the ordinary drinking variety or "common clean" rum. The " flavoured" rum is largely exported to Germany, where it is used for mixing with neutral spirit in the making of imitation rum. It may contain upwards of 2,000 parts of esters per 100,000 of alcohol. There is, however, no hard and fast line between this and the rum ordinarily used for drinking; the two classes overlap as regards chemical composit" strength, and flavour.

Fig. 41. - copper rum still.

With double retorts and condenser, commonly used in Jamaica and West Indies there is a rapid fermentation, due almost solely to yeast action, and the bacterial organisms are not allowed time to develop appreciably. Both pot-stills (or "vat" -stills, a modified form of pot-still) and continuous rectifying stills are used in distilling Demerara rum. The proportion of secondary constituents in this spirit is usually very much less than in the Jamaica product.

(Blair, Campbell & McLean, Glasgow).

Except for the alcohol and solids, all the figures are expressed in the usual units - grams per 100 litres of alcohol.

In the following table, the analyses of a few individual samples cf the above ordinary or "common clean" Jamaica rum are given as regards the secondary constituents, and also some analyses of Jamaica rum by other observers.

Jamaica rum.

In Jamaica rum the esters are nearly always more than the higher alcohols as determined by the Allen.Marquardt process, and usually very much more.

As regards Demerara rum, Prof. J. B. Harrison, the official analyst, reported in 1904 that " a rum yielding 70 to 80 parts of esters (per 100,000 of alcohol) may be considered as a characteristic rum of the type known commercially as Demerara rum."' He gives the following figures: - 1

1 Official Gazette, Demerara, Oct. 19th. 1904. Extract No. 2,083.