Friday, 17 April 2009

David Booth's description of Scotch Ale

It seems to have become Scotch Ale week here at Barclay Perkins. I hope you don't mind. There's no particular reason for it, other than that I'm currently reading a history of Wm. Younger.

The passage below neatly details all the main identifying features of Scotch Ale: high gravity, pale colour, modest hopping, high striking heat, single mash, long, cool fermentation. And definitely no effing peated malt nor roast barley in the grist.

David Booth's description of Scotch Ale
"The distinguishing characteristics of Scotch ale, are paleness of colour, and mildness of flavour. The taste of the hop never predominates, neither in its stead do we discover that of any other ingredient. It is perhaps more near to the French pale wines, than any of the other ales that are brewed in this country. Like them, too, it is the result of a lengthened fermentation.

The low heat at which the tun is pitched, confines the brewing of Scotch ale to the colder part of the year. During four or five of the summer months, the work (except perhaps in some houses for table beer) is completely at a stand, the utensils are limed down, and the greater part of the workmen discharged. No strong ale is either brewed or delivered.

The Edinburgh brewer is particularly nice in the choice of his malt and hops. The former is generally either English, or of his own making from English barley; and the latter Farnham, the finest East Kent, or a mixture of both. The yeast (or store, as it is termed) is carefully preserved, and measured into the gyle-tun, in the proportion of about three gallons to twenty barrels of wort.

The Scotch practice is to take only one mash, and that pretty stiff for strong ale, making up the quantity of wort (length) by eight or ten subsequent sprinklings of liquor over the goods, which are termed Sparges. These sparges trickle successively through the goods, and wash out as much more of the saccharine from the mash, as may suffice for the intended strength of the ale. In this manner, specific gravities may be obtained much higher than could be done by a second mash, which always requires a certain portion of liquor before the goods can be made sufficiently fluid. If we suppose this necessary portion of liquid in a particular mash to be fifteen barrels, it would be found, on trial, that these fifteen barrels, when drawn from the mash- tun, would not contain nearly so much saccharine matter as might have been extracted by ten successive sparges of a barrel each. The reason of this will be obvious, if we recollect that the grains always remain wetted with wort equivalent in strength to that of the wort last drawn off, and that the quantity remaining on the goods is about three- fourths of a barrel to a quarter of malt. The gravity of this imbibed wort will, in the one case, be equal to that of the second mash; but in the other, will be reduced to that of the tenth sparge, or washing. Mr. Richardson, so often quoted, condemns this practice ; but, in doing so, we know that he labours under a mistake. " What power," says he, " or what time, has a fluid to extract, which is sprinkled over the surface of the materials, and immediately trickles out below, without being allowed a stationary moment for infusion ?" We answer, that in malt (and it is only of malt brewings that we now speak) the infusion, if properly conducted, is. finished with the first mash,; and thaf. nothing more is necessary than to-draw out from the goods, in a pure state, that saccharine matter which the first infusion has set free. But the question with us does not depend on theory. We have brewed strong ale for years, without following it either with table beer or returns, and we have, in all cases, drawn as much from the malt as we could have done by repeated mashings. The only objection to the sparging system is the loss of time.

The first part of the process is to mash with liquor heated to 180° at least, and generally to 190°, varying with the dampness of the malt. According to Dr. Thomson, the best brewers take the lower heats, but this is doubtful. After mashing from twenty minutes to half an hour, that is, until every particle of the malt is in contact with the liquor, -the tun is covered, and the whole allowed to infuse about three hours, when it is drained off into the under back, or (what is far better) into the wort copper.

After the first wort is run off, a quantity of liquor (generally a barrel), at the heat of 180°, is sprinkled equally over the surface of the goods. To prevent the liquor from dashing on one part, it is usually received upon a circular board, about three feet diameter, which is swung over the centre of the mash-tun; and, being perforated with small holes, allows the water to descend in a shower. The board being hung on cords, is moveable by the hand over every part of the surface of the tun. When, as generally happens, the cock of the liquor-copper is not high enough to carry the liquor to the board, a separate cock is inserted in the side for that use only. Other means may be adopted to answer this purpose of sprinkling, the object being to spread the liquor, equably, in a shower over the whole surface of the goods, as if from the rose of a watering-pan.

When the barrel (or other quantity) of liquor is thus let in upon the goods, the cock of the mash-tun is opened, so as to let it off, as in the case of an ordinary mash. Some brewers, instead of the common outlet of the mash-tun, have three or four small cocks inserted in different parts of the bottom, from the fear that a single cock might draw the filtrating liquor to one point, and thereby create a crack in the goods, instead of leaving the whole of the liquor to descend in one horizontal stratum.

When the first sparge is run off, or nearly so, which may be in twenty or five and twenty minutes, another of equal quantity is put on the goods, in the same manner, and thus, successively, until the whole of the sparges, when mixed with the first mash worts, show that gravity which is desired. The strong ale worts are then completed, and a mash is made to search the goods either for table beer, or a return, as the trade requires. This mash, however, is not necessary as a saving of extract; for the whole of the saccharine matter of the malt may be exhausted, as well as any required gravity of wort produced, by means of sparges alone; but there is an opinion, probably not ill founded, that the last weak extracts are less fitted for fine ale. The making up of strengths from the coolers formerly explained, is here anticipated, being regulated by the saccharometer in the under back, or wort-copper; for practice soon teaches the increase that, is produced by the boiling. It may be here noticed, that after the first sparge at 180°, it is customary with some brewers to reduce the others gradually, so that the last is perhaps 175° or 170°.

All rankness of flavour being carefully avoided in this species of ale, the quantity of hops seldom exceeds four pounds to the quarter of malt; and the bitter thus created being too slight to cover the taste of ruder ingredients, we believe that the Edinburgh brewers have been less the prey of travelling druggists than their brethren of the south. A little honey to add to the sweet, and a few coriander seeds or other aromatics to assist the flavour, are, as far as we have learnt, the amount of the sins of which they have been accused.

The manner of boiling the worts does not differ from the directions of Mr. Richardson; but when they arrive at the gyle-tun, the process of brewing is no longer the same. The first heat of fermentation, in the Scotch method, is as low as possible, consistent with the action. The favourite heat is 50°, a point at which chemists have generally asserted that the vinous fermentation could not exist, but 45° and 46° are by no means uncommon in the manuscript brewing-books that now lie before us. Even in the coldest weather, the lowness of heat is not to be feared, provided the brewery be in full work. The fermentation sometimes continues for three weeks, and a fortnight would be a pretty fair average. Were the brewings made three times a week, seven or eight working-tuns would thus be generally in play; and these being in the same room, some of them at 12 or 15° of increased heat, would create an atmosphere for themselves.

The quantity of yeast formerly mentioned is generally sufficient, but, in some cases, an addition is made a day or two after, if, in the judgment of the brewer, it appears necessary. The least quantity that will carry forward the fermentation to the required point is always preferred; and, to assure that purpose, the tun is roused twice a day (morning and evening) to prevent its becoming too languid. This rousing is continued until the ale is nearly ready for cleansing.

The rule for cleansing differs from that given by Mr. Richardson. It is an application of his saccharometer, of which he himself was not aware. The attenuation is attended to daily, and, towards the close of the operation, twice a day. While the heat is increasing, the attenuation proceeds; that is, the weight of the worts continues to diminish. After a certain time, the heat has reached its highest point, and begins to lessen. It is here that we are directed by Mr. Richardson to trust* to the smell; but this smell merely informs us that carbonic acid continues to be evolved, and the same circumstance is, in consequence, indicated by the sac- pharometer: for as long as any such evolution of gas exists, so long will the weight of the worts continue to diminish. When the progress of the attenuation is so slow as not to exceed half a pound in twenty-four hours, it is prudent to cleanse, especially if the attenuation is already low; for it might otherwise happen, that the gas being too weak to buoy up the now close head of the tun, the yeast might partially or wholly subside, and the ale would become yeast- bitten : it would receive that disagreeable taste which the head had acquired by too long exposure to the atmospheric air.

When the ale is cleansed, the head, which has not been disturbed for two or three days, continues to float on the surface, till the whole of the then nearly pure liquid is drawn off into the casks ; and this is considered as a preservative against the admission of the atmospheric air: for (he Scotch do not skim their tuns as the London ale brewers so generally do. The ale thus cleansed does not require to be placed on close stil- lions. It throws off' little or no yeast, and a tub placed so as to catch any little overflow of the scum that arises is quite sufficient. The fermentation is almost finished in the tun ; and it is not the wish of the brewer that it should proceed much farther.

The strength of Scotch ale, when it deserves the name, ranges between thirty-two and forty-four pounds weight to the imperial barrel, that is, of a specific gravity between 1089 and 1122, according to the price at which it is meant to be sold. The general mode of charge is by the hogshead (about a barrel and a halQ, for which five pounds, six pounds, seven pounds, or eight pounds are paid, as the quality may warrant; the strength for every additional pound of price being increased by about four pounds per barrel of weight.

In a good fermentation, there seldom remains above & fourth of the original weight of the wort at the period of cleansing. Between that and a third is the usual attenuation. If above a third remains, the taste is generally mawkish, and it is to be feared that the acetous fermentation will commence, before the time in which the ale might be expected to improve. Of the less sensible process of attenuation which goes on afterwards in the casks, we have already spoken when treating generally of the "Vinous fermentation." Scotch ale soon becomes fine, and is seldom, racked, at least for the home market."
"The Art of Brewing", by David Booth, 1834, pages 52-55.

These are the examples of Scotch Ale brewing Booth gave:

There will probably be more Scotch Ale fun tomorrow. Unless something else distracts me. You know what I'm like.


Jim Johanssen said...

Ron - I have EKG hops at the ready for a Scotch Ale if could be so kind to provide a recipe (No Rush). The high strike temperature and the low fermentation temperature is much more intriguing and fun than the ESB I was going to brew. I also bought a new fridge for lagering and this would be a good first use. The Kesselmaishe lager will have to wait.


Kristen England said...

The mash for these is like the logs for the KKK beers. Mash at 165-170. I've done numerous mash experiments with these temps and even after 3 hours they still don't ferment out right. Lots of remaining starch left in the beer. Nasty off flavors.