Black Patent Malt and the Evolution of Porter

From H.S. Corran’s “A History of Brewing”

Because beer is a living thing, made from living ingredients by changing people in a changing world, it evolves. Often the explanation is “a change in public taste,” but that is always an inadequate answer. The real reasons for evolution in brewing are always complex, usually a mixture of history, economics, sociology, technology and, finally, the expectations of the drinking public.

One example of such a change occurred as the eighteenth century gave way to the nineteenth. It involved the British brewing industry a nation, at war and the invention of patent malt.

If necessity was its mother, black patent malt had plenty of grandparents. Napoleon was chief among them; the Napoleonic Wars placed a tremendous strain on the English economy from 1793 until 1815, when the British subdued the French at the Battle of Waterloo. To temper their celebrations, they lost their war with the upstart America in the same year at the Battle of New Orleans. At home, both victory and defeat were expensive. Increased taxation, 20 years of disrupted export trade and a poor domestic economy had sent malt and hop prices skyward.

Porter was the popular beer style of the time, introduced in 1722 (probably by accident, but that is another story), and its manufacture required a high percentage of brown malt. While brown malt, being more highly roasted than pale malt, could be prepared from cheaper grades of barley, the roasting also diminished the fermentable extract, and thus greater amounts of brown malt were required to produce a drink of acceptable strength.

Loss of trade and public outcry discouraged publicans from raising the price of a pot of porter, and also the brewer from raising his price to the publican. And public outrage also prevented the weakening or alteration of a brew past a certain level. Boxed in by high prices for materials on one side and the demands of the drinking public on the other, brewers sought ways to economize in the brewing process itself, the one thing still in their control.

One method was to use the more efficient pale malt for its higher fermentable matter and the standard brown malt for color and flavor only. In Ireland, the Guinness brewery experimented with this method in the manufacture of their porter. They varied the portion of brown malt from 25% to 47% in the years between 1796 and 1815.

Another alternative was to use a large portion of pale malt and add a small amount of highly roasted malt that had been darkened to the point of being scorched and burnt. This darkened the beer but also imparted a burned or tarry taste, unless the maltster had been extremely lucky in the roasting process.

In England, brewers experimented in darkening their beers with materials other than malt. With a process patented as No. 2625 in 1802, Matthew Wood evaporated wort until what remained had the color and consistency of treacle. Many London brewers colored their beers with this dark syrup. Another less popular alternative was DeRoche’s Patent No. 3263 of 1809, which involved coloring the beer with the roasted skins of pale dried malt. Still another method was to burn sugar and add it for coloring at the end of the brewing process. This, too, was a popular option with the porter brewers.

But small brewers at the end of their financial rope faced an irresistible temptation to adulterate their beer with cheap chemicals to simulate strength, color and a good head. In the public’s eyes, it was all adulteration. Brewers coloring their beers with evaporated wort and burnt sugar were lumped together with those using more pernicious chemicals and there was a strong demand for the return to pure beers made solely with malt. But brewers simply could not afford sufficient malt to do this.

From urgent necessity came invention. One maker of burnt sugar, Daniel Wheeler of Charles Street, Drury Lane, hit upon the solution. He used an iron cylinder similar in construction to a coffee roaster to roast malt to the point where a small amount of malt could darken a large amount of beer without imparting an overly burnt or tarry taste to the entire brew. According to the patent:

“Said invention consists in the heating of malt to 400 degrees and upwards of (the) Fahrenheit thermometer… and in so heating it that the greater part of the saccharine and amylaceous principles of the grain become changed into a substance resembling gum and extractive matter of a deep brown colour, readily soluble in hot or cold water…”

On March 28, 1817, he obtained British Patent No. 4112 for “A New or Improved Method of Drying and Preparation of Malt.” Historian H.S. Corran described the impact of the new innovation:

“The adoption of malt made according to Wheeler’s patent, and called ‘patent malt,’ marked the beginning of the history of porter and stout as we know it today, and put an end to the period during which the term ‘porter’ was probably applied to any brown beer to distinguish it from pale ale.”

The new process was effective, economical, produced a palatable product and freed brewers from charges of adulteration. It was quickly taken up throughout the British brewing industry. Whitbread’s Brewery recorded stocks of Patent Malt in 1817, as did Barclay’s in 1820, and Truman’s showed stocks of ‘Black Malt’ in 1826.

Records of the Guinness Brewery show their awareness of this “improved method of Browning Malt” in 1815, presumably before the patent had been granted to Wheeler. Patent Brown Malt, as it came to be called in Ireland, was described as being “more highly roasted and more highly coloured” than the ordinary brown malt, allowing a beer of the same strength and color to be made more cheaply than with the brown malt. Patent Brown Malt was used in increasing quantities and by 1828 had completely replaced brown malt.

And so porter evolved, not because of popular taste or a single brewmaster’s taste and vision, but because of Napoleon, pounds and pence, and the profit-driven ingenuity of Daniel Wheeler of Charles Street, Drury Lane.

And when the All-Malt Edition of Trivial Pursuit comes out, you will be ready when someone asks, “What’s the patent number for Black Patent Malt?”

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