Thursday, 21 July 2011

Brewing Porter the Irish way (part one)

More Mr. Morewood and his impractically-titled book. It's a pretty good book, if poorly organised. Containing such gems as this description of Porter brewing in Ireland.

It starts with a general description:

"In the brewing of porter, the first mash should be heated in the copper to 150°, in the proportion of two barrels to each quarter of malt, which ought to be a mixture of best pale and brown malt, and should be kept mashing for about three-quarters of an hour, while the liquor should remain on the goods for an hour. The tap of the mash-tun is then opened to let off the liquor as quickly as possible, and the tap should be left open till the next liquor is brought into the tun that the goods may drain. In the mean time, the second liquor has been heating, and may, in from two to three hours, have acquired the heat of 160° ; the quantity being one barrel to a quarter of malt. Mash this, for half or three quarters of an hour; let it stand for one hour, and then let it be run off in the course of half an hour more. At about five and one-half hours from the beginning, the third mash should be made at 180°, the quantity being one barrel to the quarter; mash this for half an hour, let it stand an hour and tap as before.

A fourth liquor is seldom mashed, but if it be, it may be cold or blood warm, as it is of no use but to make the sour-beer for finings ; and it is of little consequence how it is done. Some brewers use it for the first liquor of the next brewing ; but this, perhaps, is not a good plan, as it may taint the whole brewing.

These worts are to be boiled with from twelve to fourteen pounds of hops to the quarter of malt, if the liquor is intended for keeping eight or twelve months; but, in the ordinary run of porter not intended for keeping, five pounds may be sufficient. The first worts should be boiled one hour, the second two, and the third four hours.

The worts are now to be cooled down as expeditiously as the weather will permit, to about 60°, if the medium heat of the atmosphere be about 60°. If it be more or less, allowance must be made. All the three worts are to be brought together into the gyle-tun, and about five pints of yeast to the quarter of malt put in, and due time allowed for fermentation and cleansing. The criterion for cleansing is the attenuation, and one great point in porter making is, that of separating the barm completely from the liquor. The proportion of colouring is arbitrary, as it greatly depends on the colour of the malt. Formerly it was the practice to employ Socotorine aloes, in the proportion of half an ounce to a barrel, in the second worts; and to give a retentive head, as much salt of steel as would lie on a half-crown piece was added with the finings to a barrel. Quassia, in the proportion of a pound to about twenty barrels, was used as a substitute for the aloes, and copperas for the salt of steel, but these ingredients being noxious and unwholesome, have been discontinued.

As the colour of porter is chiefly to be attributed to the quantity of brown or roasted malt used, care is taken to infuse such a quantity of that material as will produce the degree of colour required, and fining is effected by isinglass dissolved in stale beer, till it becomes of a glutinous consistence, a pint of which is the usual allowance for a barrel, but sometimes more is necessary.

A good colouring article is procured by moistening a quantity of brown sugar with water, spreading it in a frying-pan to about an inch deep, placed on a fire, and stirred until it is ignited; when it is burned sufficiently, the flame is extinguished, and water is added to the residuum till it has the consistency of molasses, and it is then mixed with the worts in the copper in such quantity as the depth of colour requires."
"A philosophical and statistical history of the inventions and customs of Ancient and Modern Nations in the Manufacture and Use of Intoxicating Liquors" by Samuel Morewood, 1838, pages 628 - 629.

That's quite a detailed description of the mashing process. Here's it in tabular form:

water temp time mashed time stood barrels water per quarter
Mash 1 150º F 45 60 2
mash 2 160º F 45 60 1
mash 3 180º F 30 60 1
total 4

Three or four mashes was usual practice in the early 19th century. Except for in Scotland, where they already started sparging. The process gradually spread to England in the middle of the century.

Can you guess what's coming now? Yes, it's contextualisation time. Let's look at how that compares with the mashing methods of London Porter breweries:

Barclay Perkins TT 1832
water temp barrels water per quarter
Mash 1 158º F 2.5
mash 2 178º F 1.5
mash 3 150º F 1.66
total 5.66
Barclay Perkins brewing record document ACC/2305/1/549 held at the London Metropolitan Archives

Reid Reg (Porter) 1841
water temp barrels water per quarter
Mash 1 146º F 2.5
mash 2 157º F 1.75
mash 3 153º F 1.83
total 6.08
Reid brewing record document 789/268 held at the Westminster CityArchives

Truman Runner 1845

water temp barrels water per quarter
Mash 1 162º F 1.875
mash 2 168º F 0.875
mash 3 167º F 1.33
mash 4 166º F 2
total 6.08
Truman brewing record document B/THB/C/36 held at the London Metropolitan Archives

Two differences are evident. Firstly, London brewers used relatively more water - around 6 barrels per quarter of malt compared to just 4 in the Irish method. Secondly, the second mash had the highest strike heat in London, whereas in Ireland it was the third mash hat was hottest. Though you can see that there was considerable variation in temperatures between the London brewers.

Morewood is usefully specific about hopping rates. Let's see how those compare to London:

Hopping rates (lbs per quarter)
Running Keeping
Irish Porter 5 14
1834 Whitbread P 12.5 14.64
1834 Barclay Perkins TT 12
1830 Truman Runner 14 20.5
Whitbread brewing record document LMA/4453/D/09/027 held at the London Metropolitan Archives
Truman brewing record document B/THB/C/31 held at the London Metropolitan Archives
Barclay Perkins brewing record document ACC/2305/1/549 held at the London Metropolitan Archives

The rate given for Irish Running Porter looks very low. London brewers never went below 10 lbs per quarter. The Irish Keeping Porter figure is much more in line with London.

Next boil times. I've less London data for this as some of the older logs don't give any details of the boil. This is what I do have:

Boiling times
1st 2nd 3rd 4th
Irish Porter 1 2 4
1834 Whitbread K 1 1.5 3 4
1834 Whitbread P 1 2 3
1834 Reid Reg 1.5 1.5 4.5

Whitbread brewing record document LMA/4453/D/09/027 held at the London Metropolitan Archives
Reid brewing record document 789/268 held at the Westminster CityArchives

No great differences there. The worts are progressively boiled for longer as they get weaker. The final wort being boiled for ages in both London and Irelan.

Pitching temperatures I do have plenty of data on:

Pitching temperatures
Irish Porter 60º
1830 Truman Runner 64º
1831 Truman Keeping 64º
1834 Whitbread K 64º
1834 Whitbread P 64º
1834 Barclay Perkins TT 68º
Truman brewing record document B/THB/C/31 held at the London Metropolitan Archives
Whitbread brewing record document LMA/4453/D/09/027 held at the London Metropolitan Archives
Barclay Perkins brewing record document ACC/2305/1/549 held at the London Metropolitan Archives

The London brewers pitched at a higher temperature than that Morewood gives for Ireland. But London brewers were notorious for fermenting their Porter warm.

Finally there are all the chemicals which, thankfully, he says were no longer used. Well, not by the larger brewers. As we've recently seen, there were London brewers prosecuted for the use of salt of steel and quassia. Though in all cases they were pretty small. None of the large London Porter brewers was ever prosecuted for this type of offence.

The colouring he describes is essentia bina. Which was surely illegal in both England and Ireland in 1838. It was, briefly, legal in the 1810's but in 1816, like all forms of sugar, its use in brewing was prohibited.

Still another part to go. Where Morewood describes the Guinness brewery.


Oblivious said...

Interesting to see the fourth liquor been allow to go sour to dissolved finings instead of using some returned or stale porter mixed in a barrel.

It must also be a great my to get a lacto culture established in your brewery

The souring method in not unlike the short or no boil methods for Berliner weisse or some Belgian white beers

Gary Gillman said...

Ron, good show, but isn't the Irish porter a double stout version? I would think it would produce at least 7.0% ABV at two barrels per quarter of malt (accounting for the lower extract in the brown malt). Whereas the London beers being compared are all standard-strength porter, no?


Ron Pattinson said...

Gary, that's barrels of water for each quarter of malt. It's describing the mashing technique, not the strength of the beer.

Gary Gillman said...

Ron, thanks, I thought I read that the yield for the Irish porter in finished beer was two barrels per quarter of malt but that is not what it said, thanks for pointing that out.

Still, I wonder what the final yield was and the ABV, can you indicate that?

If you combined all the worts in London for those others, with the seemingly comparable boil times more or less, would the beer not be weaker given they started with a 1/3rd more water? I understand they could get any target gravity with parti-gyling in the 1800's sense but I mean if you simply combined the worts as Morewood said was being in done in Ireland.