It's surprising how long ago the first chemical analyses of beer were made. Fredrick Accum detailed in his 1820 work "A Treatise on Adulterations of Food" a method for discovering the alcohol content of beer. The first thing he noticed was the difference in strength between examples of the same beer sampled at the brewery and in a pub.
Brown Stout: brewery 7.25% ABV, pub 6.5% ABV
Porter: brewery 5.25% ABV, pub 4.5% ABV
Looks a bit dodgy, doesn't it. This is what Accum says:
"Whence can this difference between the beer furnished by the brewer, and that retailed by the publican, arise? We shall not be at a loss to answer this question, when we find that so many retailers of porter have been prosecuted and convicted for mixing table beer with their strong beer;"
These are the results of his (and others) analyses:
Ale, home-brewed 8.30% ABV
Ale, Burton, three samples 6.25% ABV
*Repository of Arts, No. 2, p. 74.—1816. p222
Ale, Burton* 8.88% ABV
Ale, Edinburgh* 6.20% ABV
Ale, Dorchester* 5.50% ABV
Ale, common London-brewed, six samples 5.82% ABV
Ale, Scotch, three samples 5.75% ABV
Porter, London, eight samples 4.00% ABV
Ditto, Ditto† 4.20% ABV
Ditto, Ditto† 4.45% ABV
Ditto, Ditto, bottled 4.75% ABV
Brown Stout, 4 samples 5% ABV
Ditto, Ditto† 6.80% ABV
Small Beer, six samples 0.75% ABV
Ditto, Ditto‡ 1.28% ABV
* Copied from Professor Brande’s Paper in the Philosophical Transactions, 1811, p.345.
† Result of our own Experiments, see p.174.
‡ Professor Brande’s Experiments.
Accum also has some interesting things to say about Porter and Entire and the difference between the two:
"OLD, OR ENTIRE; AND NEW, OR MILD BEER.
It is necessary to state, that every publican has two sorts of beer sent to him from the brewer; the one is called mild, which is beer sent out fresh as it is brewed; the other is called old; that is, such as is brewed on purpose for keeping, and which has been kept in store a twelve-month or eighteen months.
. . . . porter is very generally compounded of two kinds, or rather the same liquor in two different states, the due admixture of which is palatable, though neither is good alone. One is mild porter, and the other stale porter; the former is that which has a slightly bitter flavour; the latter has been kept longer. This mixture the publican adapts to the palates of his several customers, and effects the mixture very readily, by means of a machine, containing small pumps worked by handles. In these are four pumps, but only three spouts, because two of the pumps throw out at the same spout: one of these two pumps draws the mild, and the other the stale porter, from the casks down in the cellar; and the publican, by dexterously changing his hold works either pump, and draws both kinds of beer at the same spout. An indifferent observer supposes, that since it all comes from one spout, it is entire butt beer, as the publican professes over his door, and which has been decided by vulgar prejudice to be only good porter, though the difference is not easily distinguished. I have been informed by several eminent brewers, that, of late, a far greater quantity is consumed of mild than of stale beer.
The entire beer of the modern brewer, according to the statement of C. Barclay, Esq. 'consists of some beer brewed expressly for the purpose of keeping: it likewise contains a portion of returns from publicans; a portion of beer from the bottoms of vats; the beer that is drawn off from the pipes, which convey the beer from one vat to another, and from one part of the premises to another. This beer is collected and put into vats. Mr. Barclay also states that it contains a certain portion of brown stout, which is twenty shillings a barrel dearer than common beer; and some bottling beer, which is ten shillings a barrel dearer; and that all these beers, united, are put into vats, and that it depends upon various circumstances, how long they may remain in those vats before they become perfectly bright. When bright, this beer is sent out to the publicans, for their entire beer, and there is sometimes a small quantity of mild beer mixed with it.'
The present entire beer, therefore, is a very heterogeneous mixture, composed of all the waste and spoiled beer of the publicans—the bottoms of butts—the leavings of the pots—the drippings of the machines for drawing the beer—the remnants of beer that lay in the leaden pipes of the brewery, with a portion of brown stout, bottling beer, and mild beer."
Source: Fredrick Accum "A Treatise on Adulterations of Food", pages 197 - 202
Entire sounds delighful, doesn't it? Mmm slops, lead-laden beer and a bit of Brown Stout. "Quart of Entire please, barman, and make it good and leady." I liked the imaginative use of beer engines to mix stale and mild Porter whilst pouring. I wonder if anyone still has a set with four handles but only three spouts?
It's reading passages like this that makes me realise how difficult it would be to truly recreate early 19th-century Porter. Reading the brewing logs is one thing, but as the beer never seems to have been consumed in its pristine state, they don't tell you the whole story. Sadly, I think health inspectors might prevent a faithful recreation.