War with the French

Porter wasn’t a static thing, it continued to develop during the 1700s. Moving away from its origins as a 100% brown malt beer.

Towards the end of the 18th century, almost constant war with the French left the British government in need of cash. And they turned to their favourite source of revenue: alcohol. At the time, beer was taxed in three ways: on the malt, on the hops and on the finished beer itself.

A combination of increased taxation on malt to pay for the wars with France and the introduction of new technology, in the form of the hydrometer, transformed Porter grists. Brewers realised that, though cheaper, the poorer yield from brown malt actually made it more expensive to use than pale malt. The base malt changed from brown to pale, with brown retained just for flavour and colour.

It’s likely that this is when brown malt stopped being diastatic. With a majority of the malt pale, there was no need for the brown malt to retain any diastatic power. At a time when it was also required to provide more colour and flavour than previously.

At this point London brewers still used ingredients from the immediate area: malt from Hertfordshire or Sussex and hops from Kent. This would change radically in just a couple of decades as the UK’s population and thirst for beer outstripped the productive capacity of agriculture.

The increased taxation had a couple of effects on Porter. The first was the move away from a 100% brown malt beer to one brewed from a base of pale malt. But it retained a high percentage of brown malt.

The second change was a reduction in OG. Dropping from 1075º in the 1770s to around 1055º by the first years of the 19th century. This was as a direct result of increased taxation, which encouraged brewers to lower strength to cut costs.

Taxes on beer 1779 - 1815
Year	Tax/bush.malt	tax/lb. Hops	tax/brl strong	tax/brl small	tax/brl table	Price quart porter
1779	9.25d	1d + 5%	8s	1s 4d	2s	3.5d
1780	1s 4.25d	1d + 10%	8s	1s 4d	2s	3.5d
1783	1s 4.25d	1d + 15%	8s	1s 4d	3s	3.5d
1786	1s 4.25d	1.6d	8s	1s 4d	3s	3.5d
1791	1s 7.25d	1.6d	8s	1s 4d	3s	3.5d
1801	1s 4.25d	2.5d	8s	1s 4d	3s	4.5d
1802	2s. 5d	2.5d	10s		2s	4d
1804	4s 5.75d	2.5d	10s		2s	6d
1815	2s. 5d	2d	10s		2s
Sources:
The Brewing Industry in England 1700-1830 Peter Mathias, p.369
A History of English Ale and Beer, H.A. Monckton, p.204

Porter before black malt
Year	Brewer	OG	FG	ABV	App. Atten-uation	lbs hops/ qtr	hops lb/brl	pale malt	brown malt	amber malt
1804	Barclay Perkins	1055.4	1015.5	5.28	72.02%	6.83	2.00	42.59%	47.43%	9.98%
1807	Whitbread	1052.6	1015.5	4.91	70.53%	13.06	3.60	66.32%	16.84%	16.84%
Sources:
Whitbread brewing record held at the London Metropolitan archives, document number LMA/4453/D/09/002.
Barclay Perkins brewing record held at the London Metropolitan archives, document number ACC/2305/1/525.

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