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I promised you some more details about attenuation. It seems like just yesterday. Oh, it was yesterday. That explains things.

The following is taken from the report of the Analytical Sanitary Commission set up to investigate allegations of strychnine in Pale Ale. It was published in The Lancet. Of course they didn't find any strychnine in Bass or Allsopp beer. They did uncover some rather more useful information about the constituents of Pale Ale.


"Analyses Showing The Composition And Strength Of Messrs. Allsopp And Sons, And Messrs. Bass And Co.'s Bitter Beers.

No. 1.
Analysis of Beer brewed March, 1851, by Messrs. Allsopp and Sons, for Exportation to India. Selected from the Stores at Blackwall of Messrs. Friend and Co.
(Contents of Imperial Gallon.)


grains Sugar 200 Gum 2,080 Bitter extract 810 Total solid exrtract 3,090 Alcohol, of spec.grav .794 3540 Water 63,370
70,000 Per-centage of alcohol, 5.05



No. 2.
Analysis of Beer brewed March 20th, 1851, by Messrs. Allsopp and Sons, for Exportation, selected from the Stores at Blackwall of Messrs. Byass and Co.
(Contents of Imperial Gallon.)

Sugar 320 grains Gum 2,110 Bitter extract 750 Total solid extract 3,180 Alcohol, of spec.grav .794 3820 Water 63,000
70,000 Per-centage of alcohol, 5 46.



No. 3.
Analysis of Beer brewed March 3rd, 1852, by Messrs. Bass and Co., for home consumption. From the Stores at Blackwall.
(Contents of Imperial Gallon.)


grains Sugar 390 Gum 3,930 Bitter extract 760 Total solid extract 5,080 Alcohol, of spec. grav. .794 3,983 Water 60,937
70,000 Per-centage of alcohol, 5.69.


No. 4.
Analysis of Beer brewed November 25th, 1851, by Messrs.Bass and Co., for home consumption. From the Stores at Blackwall.
(Contents of Imperial Gallon.)


grains Sugar 420 Gum 2,660 Bitter extract 800 Total solid extract 3,880 Alcohol, of spec. grav. .794 3,744 Water 62,376
70,000 Per-centage of alcohol, 5.34


The different ages of the beers sufficiently explain the slight variations in the results of the preceding analyses. The above general analyses are important. They show—

1st.—That the bitter beers of Messrs. Allsopp and Sons, and of Messrs. Bass and Co., contain only a moderate amount of alcohol; and

2nd.—That they contain an unusually large quantity of bitter extract, consisting of the extract of hops.

In estimating the quality and condition of beer, it is of great importance to ascertain its specific gravity, since this indicates to a considerable extent the amount of solid contents or extractive matter in the beer, which, as a rule, is in the newest and strongest beers.

It should be remembered, however, that alcohol, lighter than water, conceals in some measure the extract as estimated by the hydrometer, rendering the beer by so much the less dense as the proportion of alcohol is greatest.

It should also be borne in mind that the sugar, as the beer ages, gradually becomes converted into alcohol, and this again into acetic acid, and hence old beers usually possess a low specific gravity.

The effect of age in diminishing the density of beer is clearly shown in the following tables of specific gravities:—

Table showing the Specific Gravities of different Samples of Beer of various ages brewed by Messrs. Allsopp and Sons.

Specific grav.

1. —From the Stores at Blackwall, for home trade, brewed March 23rd, 1852 1020
2. —From the Stores at Blackwall, for home trade, brewed Dec. 1851 1017
3. —From the Stores at Blackwall, for exportation, brewed February 27th, 1852 1019
4. —From the Stores at Blackwall, for exportation, brewed March, 1852 1019
5.—From the Stock of Messrs. Wallis and Co., agents for home trade, brewed October, 1851 1019
6. —From the Stock of Messrs. Child and Co., agents for home trade 1015
7. —From the Stock of Messrs. Findlater, Mackie, and Co., agents for home trade 1016
8. —From the Stock of Messrs. Daukes and Rodick, agents for home trade 1015
9. —From the Stock of Messrs. Foster and Sons, agents for home trade 1014
10. —From the Stock of Mr. Bovill, agent, brewed Nov. 1851 1015
11. —From the Stock of Mr. Bovill, agent, brewed Jan. 1851 1009
12. —From the Stock of Mr. Bovill, agent, brewed Dec. 23, 1850 1006
13. —From the Stock of Messrs. Hibbert, agents for exportation 1007
14. —From the Stock of Messrs. Friend and Co., at Blackwall, agents for exportation, brewed March, 1851 1008
15. —From the Stores of Messrs. Byass and Co., at Blackwall, agents for exportation, brewed March 1851 1009


Table showing the Specific Gravities of different Samples of Beer of various ages, brewed by Messrs. Bass and Co.

1. —From the Stores at Blackwall, for home trade, brewed April 27th, 1852 1024
2. —From the Stores at Blackwall, for home trade, brewed April 28th, 1852 1024
3.—From the Stores at Blackwall, for home trade, brewed March 3rd, 1852 1019
4.—From the Stores at Blackwall, for home trade, brewed November 25th, 1851 1013
5. —From the Stores at Blackwall, for exportation, brewed February 18th, 1852 1021
6. —From the Stores at Blackwall, for exportation, brewed February 19th, 1852 1021
7.—From the Stores at Blackwall, for exportation, brewed March 25th, 1852 1022
8. —From the Stock of Messrs. Saunders and Cameron, agents for home trade 1015
9. —From the Stock of Messrs. Daukes and Rodick, agents for home trade 1016
10. —From the Stock of Mr. Favenc, agent for home trade 1015
11.—From the Stock of Messrs. Kinahan, agents for home trade 1012
12.—From the Stock of Messrs. Crimp and Ward, export agents, brewed January, 1852 1015
13. —From the Stock of Messrs. Crimp and Ward, agents for exportation, brewed December, 1851 1009
14. —From the Stock of Mr. Dalston, agent, brewed 1850 1006


The above tables prove that the density of beers differs remarkably with age."
"The Lancet 1852, vol.1", 1852, pages 474 - 475.
To begin, I'll emphasise that the chemists analysing Pale Ale didn't consider it strong: "the bitter beers of Messrs. Allsopp and Sons, and of Messrs. Bass and Co., contain only a moderate amount of alcohol". You know what's coming now. IPA was not a strong beer. The percentages given are by weight, but after converting them to ABV, the strongest is still only just over 7%. And that wasn't for export, but home consumption.

The analyses also confirm the large quantity of hops used. Not a real surprise, but nice to see numbers to back it up.

Finally lets get to the point of this post. Final gravities. Examples 3 and 4 from Allsopp, brewed in February and March 1852 have a significantly higher gravity than examples 14 and 15, brewed a year earlier. All were meant for export. The younger beers are both 1019, the older beers 1008 and 1009.

There's the same pattern with the Bass samples. The two oldest, examples 4 and 14, have the lowest gravity. The two youngest, examples 1 and 2, the highest gravity.

That looks like proof to me that during the extended storage of Pale Ale before sale a secondary fermentation took place. One that approximately halved the gravity of the beer.


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