First, that they couldn't decide on the brewhouse name, calling it both P and BS. The latter name, presumably short for Brown Stout, would imply it was a Stout. Then why sometimes call it P? And in terms of gravity, it's definitely in Porter rather than Stout territory.
The level of attenuation is very patchy, varying from 57% to 73%. The top end is what I would have expected. In the 1850's and 1860's, London Porter was 70-75% attenuated.
In some ways these Porters are very unlike Younger's other beers. The boils - especially in the 1850's - were longer. Their other beers were boiled for 90 minutes at most. The difference wasn't as big in the 1860's, but was still there. The pitching temperature of the Porters was higher - other beers were pitched at 56-60º F, as was the maximum fermentation temperature, which for other styles didn't exceed 70º F. Unsurprisingly given the higher temperature, the fermentation was also shorter, by one to three days.
In the 1850's, the hopping levels were similar to in London: 2.75-3 lbs per barrel. By the 1860's, they'd fallen to about half the level in London, where the hopping rate had remained constant.
I've been saving the oddest until the last: the grists. The percentage of brown malt is very high in the examples from the 1850's. So high that they must have been using diastatic brown malt, something that I thought had disappeared before this date. The pale malt percentage was more normal-looking in the 1860's, but the percentage of amber malt is very high in some examples. Note that brown malt had been dropped by then.
Other than the single example that's just pale and black malt, none of the grists look like English ones. It's all very odd.
|William Younger Porter 1851 - 1869|
|Year||Beer||OG||FG||ABV||App. Atten-uation||lbs hops/ qtr||hops lb/brl||boil time (hours)||boil time (hours)||Pitch temp||max. fermen-tation temp||length of fermen-tation (days)||pale malt||brown malt||black malt||amber malt|
|1851||BS||1057||1017||5.29||70.18%||21.75||3.08||2.25||64º||73º||3 + 2||42.92%||32.45%||24.63%|
|1851||BS||1056||1015||5.42||73.21%||23.87||2.86||2.25||63º||72º||4 + 1||24.73%||56.08%||19.19%|
|1851||BS||1060||1022||5.03||63.33%||23.46||2.61||2.25||63º||72º||3 + 2||24.32%||55.16%||20.52%|
|1851||BS||1060||1021||5.16||65.00%||25.26||2.93||2.5||64º||73º||3 + 2||26.08%||59.14%||14.78%|
|1851||BS||1060||1024||4.76||60.00%||27.37||3.17||2.25||64º||71º||3 + 2||26.08%||59.14%||14.78%|
|1851||BS||1063||1023||5.29||63.49%||7.50||0.91||2||64º||72º||3 + 1||30.60%||69.40%|
|1852||BS||1057||1018||5.16||68.42%||23.87||2.93||2.25||64º||72º||3 + 3||24.73%||56.08%||19.19%|
|1858||BS||1052||1022||3.97||57.69%||18.33||2.75||2||61º||72º||3 + 3||56.95%||14.35%||14.35%||14.35%|
|1858||BS||1054||1022||4.23||59.26%||16.67||2.22||2.33||62º||72º||3 + 2||56.95%||14.35%||28.70%|
|1868||Bg||1046||1020||3.44||56.52%||8.00||1.45||3||61º||69º||3 + 2||92.25%||7.75%|
|1869||BS||1041||1017||3.18||58.54%||7.69||1.18||2.5||3||61º||66º||2 + 3||45.26%||13.69%||41.06%|
|1869||P||1048||1018||3.97||62.50%||2.75||62º||67º||2 + 1||68.80%||10.40%||20.80%|
|1869||BS||1042||1018||3.18||57.14%||7.50||1.46||2.5||3||61º||67º||2 + 3||68.80%||10.40%||20.80%|
|William Younger brewing records held at the Scottish Brewing Archive, document numbers WY/6/1/2/5, WY/6/1/2/14 and WY/6/1/2/21.|