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|
|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|
|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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