The method of brewing porter has not been the same at all times as it is at present.
At first, the only essential difference in the methods of brewing this liquor and that of other kinds of beer, was, that porter was brewed from brown malt only; and this gave to it both the colour and flavour required. Of late years it has been brewed from mixtures of pale and brown malt.
These, at some establishments, are mashed separately, and the worts from each are afterwards mixed together. The proportion of pale and brown malt, used for brewing porter, varies in different breweries; some employ nearly two parts of pale malt and one part of brown malt; but each brewer appears to have his own proportion; which the intelligent manufacturer varies, according to the nature and qualities of the malt. Three pounds of hops are, upon an average, allowed to every barrel, (thirty-six gallons) of porter.
When the price of malt, on account of the great increase in the price of barley during the late war, was very high, the London brewers discovered that a larger quantity of wort of a given strength could be obtained from pale malt than from brown malt. They therefore increased the quantity of the former and diminished that of the latter. This produced beer of a paler colour, and of a less bitter flavour. To remedy these disadvantages, they invented an artificial colouring substance, prepared by boiling brown sugar till it acquired a very dark brown colour; a solution of which was employed to darken the colour of the beer. Some brewers made use of the infusion of malt instead of sugar colouring. To impart to the beer a bitter taste, the fraudulent brewer employed quassia wood and wormwood as a substitute for hops.
But as the colouring of beer by means of sugar became in many instances a pretext for using illegal ingredients, the Legislature, apprehensive from the mischief that might, and actually did, result from it, passed an Act prohibiting the use of burnt sugar, in July 1817; and nothing but malt and hops is now allowed to enter into the composition of beer: even the use of isinglass for clarifying beer, is contrary to law.
No sooner had the beer-colouring Act been repealed, than other persons obtained a patent for effecting the purpose of imparting an artificial colour to porter, by means of brown malt, specifically prepared for that purpose only. The beer, coloured by the new method, is more liable to become spoiled, than when coloured by the process formerly practised. The colouring malt does not contain any considerable portion of saccharine matter. The grain is by mere torrefaction converted into a gum-like substance, wholly soluble in water, which renders the beer more liable to pass into the acetous fermentation than the common brown malt is capable of doing; because the latter, if prepared from good barley, contains a portion of saccharine matter, of which the patent malt is destitute.
But as brown malt is generally prepared from the worst kind of barley, and as the patent malt can only be made from good grain, it may become, on that account, an useful article to the brewer (at least, it gives colour and body to the beer;) but it cannot materially economise the quantity of malt necessary to produce good porter. Some brewers of eminence in this town have assured me, that the use of this mode of colouring beer is wholly unnecessary; and that porter of the requisite colour may be brewed better without it; hence this kind of malt is not used in their establishments. The quantity of gum-like matter which it contains, gives too much ferment to the beer, and renders it liable to spoil. Repeated experiments, made on a large scale, have settled this fact.
STRENGTH AND SPECIFIC DIFFERENCES OF DIFFERENT KINDS OF PORTER.
The strength of all kinds of beer, like that of wine, depends on the quantity of spirit contained in a given bulk of the liquor.