Tuesday 29 January 2008

Scotch Ale II

I seem to remember posting something about Scotch Ale a while back. One of my main points was that the don't-use-many-hops-because they-don't-grow-in-Scotland story about Scotch Ale was just that: a story. Well, I've been poking around a bit more. Perhaps I was a little hasty in my assessment.

This a description of how to brew Scotch Ale written in the 1850's.
"We shall add a few observations upon the brewing of Scotch ale. This beverage is characterized by its pale amber color, and its mild balsamic flavor. The bitterness of the hop is so mellowed with the malt as not to predominate. The ale of Preston Pans is, in fact, the best substitute for wine which barley has hitherto produced. The low temperature at which the Scotch brewer pitches his fermenting tun restricts his labors to the colder months of the year. He does nothing during four of the summer months. He is extremely nice in selecting his malt and hops; the former being made from the best English barley, and the latter being the growth of Farnham or East Kent. The yeast is carefully looked after, and measured into the fermenting tun in the proportion of one gallon to 240 gallons of wort.

Only one mash is made by the Scotch ale brewer, and that pretty strong; but the malt is exhausted by eight or ten successive sprinklings of liquor (hot water) over the goods (malt), which are termed in the vernacular tongue, sparges. These waterings percolate through the malt on the mash-tun bottom, and extract as much of the saccharine matter as may be sufficient for the brewing. By this simple method much higher specific gravities may be obtained than would be practicable by a second mash. With malt, the infusion or saccharine fermentation of the diastase is finished with the first mash; and nothing remains but to wash away from the goods the matter which that process has rendered soluble. It will be found on trial that 20 barrels of wort drawn from a certain quantity of malt, by two successive mashings, will not be so rich in fermentable matter as 20 barrels extracted by ten successive sparges of two barrels each. The grains always remain soaked with wort like that just drawn off, and the total residual quantity is three fourths of a barrel for every quarter of malt. The gravity of this residual wort will on the first plan be equal to that of the second mash; but on the second plan, it will be equal only to that of the tenth sparge, and will be more attenuated in a very high geometrical ratio. The only serious objection to the sparging system is the loss of time by the successive drainages. A mash-tun with a steam jacket promises to suit the sparging system well; as it would keep up a uniform temperature in the goods, without requiring them to be sparged with very hot liquor.

The first part of the Scotch process seems of doubtful economy; for the mash liquor is heated so high as 180°. After mashing for about half an hour, or till every particle of the malt is thoroughly drenched, the tun is covered, and the mixture left to infuse about three hours; it is then drained off into the under-back, or preferably into the wort copper.

After this wort is run off, a quantity of liquor (water), at 180° of heat, is sprinkled uniformly over the surface of the malt; being first dashed on a perforated circular board, suspended horizontally over the mash-tun, wherefrom it descends like a shower upon the whole of the goods. The percolating wort is allowed to flow off, by three or more small stopcocks round the circumference of the mash-tun, to ensure the equal diffusion of the liquor.

The first sparge being run off in the course of twenty minutes, another similar one is infused; and thus in succession till the whole of the drainage, when mixed with the first mash-wort, constitutes the density adapted to the quality of the ale. Thus, the strong worts are prepared, and the malt is exhausted either for table beer, or for a return, as pointed out above. The last sparges are made 5° or 6° cooler than the first.

The quantity of hops seldom exceeds four pounds to the quarter of malt. The manner of boiling the worts is the same as that above described; but the conduct of the fermentation is peculiar. The heat is pitched at 50°, and the fermentation continues from a fortnight to three weeks. Were three brewings made in the week, seven or eight working tuns would thus be in constant action; and, as they are usually in one room, and some of them at an elevation of temperature of 15°, the apartment must be propitious to fermentation, however low its heat may be at the commencement. No more yeast is used than is indispensable; if a little more be needed, it is made effective by rousing up the tuns twice a day from the bottom.

When the progress of the attenuation becomes so slack as not to exceed half a pound in the day, it is prudent to cleanse, otherwise the top-barm might re-enter the body of the beer, and it would become yeast-bitter. When the ale is cleansed, the head, which has not been disturbed for some days, is allowed to float on the surface till the whole of the the pure ale is drawn off into the casks. This top is regarded as a sufficient preservative against the contact of the atmosphere. The Scotch do not skim their tuns, as the London ale brewers commonly do. The Scotch ale, when so cleansed, does not require to be set upon close stillions. It throws off little or no yeast, because the fermentation has nearly finished in the tun. The strength of the best Scotch ale ranges between 32 and 44 pounds to the barrel; or it has a specific gravity of from 1.088 to 1.122, according to the price at which it is sold. In a good fermentation, seldom more than a fourth of theoretical gravity of the wort remains at the period of the cleansing. Between one third and one fourth is the usual degree of attenuation. Scotch ale soon becomes fine, and is seldom racked for the home market. The following table will show the progress of fermentation in a brewing of good Scotch ale:

20 barrels of mash-worts of 42.5 pounds gravity = 860.6
20 — returns 6.1 = 122
12 ) 982.6
pounds weight of extract per quarter of malt = 81

Fermentation :—
March 24. pitched the tun at 51° : yeast 4 gallons.
Temp. Gravity
25. 52° 41 pounds.
28. 56° 39
30. 60° 34
April 1. 62° 32
4. 65° 29 added 1 Ib. of yeast
5. 66° 26
6. 67° 23
7. 67° 20
8. 66° 18
9. 66° 15
10. 64° 14.5 cleansed"

"A Dictionary of Arts, Manufactures, and Mines" by Andrew Ure, New York 1858, Pages 142 - 143
The main features of the method outlined are:
  1. a single mash followed by multiple sparges
  2. a long, slow fermentation
  3. low hopping-rate - just 4 pounds per quarter of malt. In 1850, Truman's Porter and Stouts were hopped at between 11 and 22 pounds per quarter. In 1838/9 Griffin Brewery's X Ales had between 7 and 8 pounds of hops per quarter.
  4. it was neither racked nor fined (a publican who sold Younger's in the 1970's once told me that he had a barrel that wouldn't clear and S & N suggested that he fined it - something that even then wasn't done in the brewery)

Can we trust this description? It wasn't in a specialist brewing manual, but a more general publication. "Scottish Ale Brewer" by W.H. Roberts, 1847 (page 108) confirms the bit about fermentation temperatures:
". . while the English brewers frequently set their wots as high as 75º, or, acording to some practical writers, occasionally 80º, the Scottish seldom if ever exceed 58º, and, in some cases, fall so low as 44º.
. . . it is not uncommon for Scottish brewers to have their gyles in the tun for twenty-one days, whilst in England, so long a period as even six days is considered as of rare occurrence."
What about the low hopping rate? Is that true? I'm beginning to believe it was. In the case of Scotch Ale. But that was a specific style of beer. Not everything brewed in Scotland was Scotch Ale. By the 1840's Edinburgh had become a major producer (and exporter) of IPA. This, of course, was hopped like crazy.

English Ale of the period was also lightly-hopped - between 7 and 8 pounds of hops per quarter of malt. This what W.H. Roberts, (pages 89-90) has to say about hopping rates:
"With regard to the quantity of hops which the brewers in Scotland use for each quarter of malt, it is impossible to fix any certain data, as it varies from four to eight pounds, according to the quality of the ale, and the season of the year. In winter-brewings, six pounds of hops for the best ale, and four pounds for the inferior kinds, may be considered a fair estimate.

Our practice of brewing, from January to March, was to allow ten pounds of hops per quarter of malt, when the wort was from 96 to 100 of specific gravity. Four pounds of hops were put into the copper when the wort was about 200º of heat, and boiled briskly for the space of twenty minutes; and the remaining six pounds were then added and allowed to boil thirty of forty minutes, according to circumstances. If the gravity of the wort was from 85 to 90, we only made use of eight instead of ten pounds per quarter, boiling four pounds for fifteen minutes , and the remaining four pounds from forty to fifty minutes, as mentioned above. But if the gravity of the wort was only 70 to 80, seven pounds a quarter only were employed. Two pounds of these were boiled for twenty minutes, and the remaining five pounds put in and boiled for forty or fifty minutes, as before."
So was Scottish beer lightly hopped? Yes and no. It depends which type of beer you're talking about. Not all Scottish Ale was Scotch Ale.

1 comment:

Boak said...

So the word "sparge" is considered to be part of the vernacular? What did the poshos call it?