the general consideration the first two examples, the proportion evaporated would have been still greater.
When the wort is let out of the boiler into the cooler, the hops still remain, and, as they are soaked with wort, a considerable loss would be sustained if they were thrown away. Thus we found, in one instance, that 45 lbs. of hops retained half a barrel of wort after they were drained so completely that no more wort would drop out. In another case, 35 lbs. of hops retained in the same way 0*3666 of a barrel, which is rather more than one-third of a barrel. To recover this wort it is proper to subject the hops to pressure. We do not know whether this is attended to by the great brewers, though it probably is. By several of the Edinburgh brewers it is, we believe, too much neglected.
In cold weather, where the brewery is small, and the apartment in which the fermenting vessels are placed, cold, it is proper not to reduce the temperature of the wort as low as that of the atmosphere. From want of attention to this circumstance, we have seen wort refuse to ferment for some time, and the brewer under the necessity of heating it artificially before fermentation could be brought on. In stch cases the wort is very apt to be lost altogether by contracting acidity. The temperature, in such cases, ought not to be reduced lower than 56°. But when the apartment in which fermentation is carried on is warm, 51° or 52° is a very good temperature. When the brewer is obliged to make ale in warm summer weather, it is material to reduce the temperature as low as possible. In such cases great advantage would attend cooling the wort in coolers without any roof or covering whatever, but quite open to the sky ; because in clear nights, the wort might be cooled in this way, eight or ten degrees lower than the temperature of the atmosphere. The reason is obvious. It is owing to the rays of heat, which, in such a case, radiate from the wort, and are not returned again by the clear sky. Wort, being a good radiator of heat, would be particularly benefited by this method of cooling. We have no doubt that it might be put in practice with advantage in hot climates ; and that, by means of it, good ale or porter might be manufactured in the East and West Indies. Such a manufacture, if successful, would be particularly relished in India, and would, we doubt not, prove a lucrative article of manufacture to an enterprising man.
While a duty was levied on ale and beer according to their quantity, excisemen were in the habit of gauging the wort while in the boiler and when on the coolers. Not that the duty was levied according to the quantities there found, but to serve as a check upon the more accurate gauges taken in the ferment-ing-tuns. For a certain allowance being made for evaporation while the wort is in the cooler, which the excisemen, from long observation, are enabled to do with some accuracy, they have it in their power, from these checks, to determine whether any of the worff from the coolers h^s been secreted or carried off with a view to evade the excise laws. In the year 1880 the duty on beer was taken off. The consequence of this is, that the brewer is now entirely freed from tEe exciseman, and at liberty to improve his processes at pleasure. We doubt not that in a short time this will be followed by considerable improvements in brewing.*
* The following communication to the author of this treatise, on the mode of cooling wort with the smallest loss of saccharine matter, deserves the attention of the brewer :—■
From a given quantity of malt, required the greatest possible weight of the solid extract of saccharum in solution at the fermentation point.
The first step is to prove the weight of the saccharine extract from the mash, and to shew the loss in each succeeding part of the process.
In every brewing, from fair average pale malt, when the weight in lbs. of the solid extract of saccharum per barrel, as indicated by the saccharometer, is multiplied by the number of barrels of wort obtained from the mash, and the product divided by the number of bushels of malt in operation ; the maximum weight of saccharine extract per bushel will be found. Pursuing the same method to ascertain the loss of saccharum by evaporation in boiling and cooling down the wort to the fermentation point, an approximation is obtained—
Weight of saccharum from the mash, 28 lbs. per bushel.
as the average weight at the point of fermentation obtained by ale-brewers by the present method of brewing, being a loss of 12£ per cent, of the whole saccharum obtained from the malt in operation.
4. When the wort is sufficiently cooled down by exposure on the coolers, it is let down into the fer-mentingj-tuns, or, as the brewers call them, the gyle-
To prevent part of this loss, and to establish a method of brew-ing, by which the greatest possible quantity of wort, and weight of the solid extract may be brought down to the point of fermentation, is the next step to which the attention of brewers may be called.
A sample of wort was drawn from the boiler, just before the contents were run into the coolers. The tin jar was immediately plunged into a pail of cold water, and the process of cooling by evaporation was superseded by the caloric being transmitted through the sides of the jar, by the action of the water on every part of its surface. The contents of the jar, and the worts in the cooler, being accurately weighed both at 60®, the real strength of the wort in the boiler, and loss by evaporation on the coolers, were determined.
On making this trial it became obvious, that, were an elongated square utensil filled with wort, and placed in a horizontal position, and a stream of cold water run continuously over the surface, the process of cooling would rapidly go on without any loss whatever, either by evaporation of the wort or destruction of the saccharum. The action of refrigeration would be vertical, and the fecula of the wort would be as effectually precipitated, as during the process of cooling by evaporation in the open coolers.
On subjecting the wort to experiment on a small scale, the success was complete; and I believe it has only to undergo a fair trial to become a most important and valuable acquisition to brewers and distillers.
On constructing a cooler on this new principle, it would be requisite to make it at once simple and perfect, to fit it for practical utility, in which view I would unite the hop-drainer, on the most improved construction, to it, making the hop-drainer a reservoir to keep the cooler continually full; and thuB save the whole wort and extract lost by the present method of evaporation on the coolers.
The refrigeratory power of such a cooler is very great, as the liquid within must cool down to the degree of heat of the substance which is applied to the surface ; so that, in addition to cold tuns, in order to be fermented; by which process it is converted from the luscious, sweet-tasted liquor called wort, to the brisk intoxicating liquor which constitutes ale. The gyle-tuns are cylindrical wooden vessels, varying in size according to the extent of the brewery. In the London breweries, and in the distilleries, they are of prodigious size; but in private houses they often do not exceed the size of a wine-hogshead, or even of a beer-barrel. The fermentation is perhaps conducted with the greatest economy in large vessels; but good ale may be made in comparatively small quantities. How far this is the case with porter, it is more difficult to say. Good porter has scarcely ever been made, except by those who manufacture it upon a large scale.
The fermenting-tuns are not to be filled by the wort, because a considerable increase in bulk takes place during the fermentation, in consequence of water, were ice used, refrigeration may be carried rapidly down to the freezing-point in any experiment that may be tried.
With regard to boiling, during which so large a destruction of wort and saccharum takes place, the subject is one of difficulty.
The double-boiler, used in the London breweries, might be adopted by ale-brewers towards avoiding part of the loss. It must act under diminished atmospheric pressure, and save part of the saccharum and wort; but the capacity of the saccharum to escape being greatest at the boiling point, the destruction must go on to a great extent in it also. The best form, perhaps, would be the common boiler, with an upper back, so constructed as to present as small a surface as possible to the action of evaporation; and by regulating the time of boiling,—and this is particularly requisite in the English method of brewing,—I am certain a saving of 1 lb. per bushel may be effected on the whole malt in operation.—W. S.
which the liquor would run over, unless allowance were made for it.
The fermentation of ale or beer is never carried to any great length. The object of the brewer is, to retain the flavour and good qualities of the ale or beer, not to develop the greatest quantity of spirits, which can hardly be done without allowing the wort to run into acidity. The violence of the fermentation depends upon the quantity of yeast added. Brewers, accordingly, mix yeast with their worts only in very sparing quantities, while the distiller adds it in great doses, and repeatedly.
Yeast is a frothy substance, of a brownish-grey colour and bitter taste, which is formed on the surface of ale or wine while fermenting. If it be put into sacks, the moisture gradually drops out, and the yeast remains behind in a solid form. It has very much of the flavour and taste of cheese when in this state; but its colour is still darker. This dried yeast promotes or excites fermentation, but it does not answer quite so well as fresh yeast. At one period, some of the Scotch distillers employed.considerable quantities of it; but all of them with whom we conversed on the subject affirmed, that it was much less profitable than even the bad porter yeast which they Were in the habit of bringing down from London. From the resemblance which dried yeast has to cheese, one would be disposed to infer, that it is a species or variety of gluten. But if we attempt to induce fermentation in wort by adding the gluten of wheat, we will be unsuccessful.
When yeast is kept for some time in cylindrical glass vessels, a white substance, not unlike curd, separates and swims on the surface. If this substance be removed, the yeast loses the property of exciting fermentation. This white substance possesses many of the properties of gluten, or vegetable fibrin, though it differs from it in others. Its eolour is much whiter; it has not the same elasticity, and its particles do not adhere with the same force. In short, it agrees much more nearly, in its properties, with the curd of milk than with the gluten of wheat. We are disposed to consider this substance as the true fermenting principle in yeast, though we were never able to procure a sufficient quantity of it to put its fermenting powers to the test of experiment. We have sometimes seen a similar substance separate in the fermenting-tuns in distilleries, when the fermentation was nearly at an end; or, rather, when such a quantity of spirit had been generated as put an end to the fermenting process altogether. But we could never learn that the distillers had formed any opinion respecting this curdy substance. It did not interfere with the success of their operations, and, on that account, they bestowed little attention on it. We attempted, once or twice, to collect such a quantity of it as might enable us to try its powers as a ferment, but we did not succeed.
The only chemist who has attempted to subject yeast to a chemical analysis is Westrumb ; but, though this philosopher was distinguished for his accuracy, the task was too difficult for the resources of the science of the time (1796) when he published his Experiments. From 15,360 parts of fresh beer yeast, he obtained the following substances :—
Carbonic acid, 15 m
Acetic acid 10
Malic acid, 45
Saccharine matter, 315
As yeast may be reduced to a dried state without depriving it of the power of acting as a ferment, it is clear that the carbonic acid, acetic acid, alcohol, and water, are not essential to it. We cannot suppose that either potash, lime, or malic acid, is essential. The saccharine matter, we know, is capable of fermenting of itself; but if it were the essential ingredient, it would be quite unnecessary to add yeast to wort at all, as we know that the wort contains abundance of saccharine matter in solution. We
know likewise, from experiment, that neither extractive, mucilage, nor gluten, possesses the property of exciting fermentation. Thus, none of thfc substances found by Westrumb in yeast, can be considered as the true fermenting principle. Dobereiner found, that, when yeast is steeped in alcohol, it loses the property of acting as a ferment. This may be owing to the alcohol dissolving and carrying off the true fermenting principle. But we are rather disposed to ascribe it to the presence of a portion of alcohol in the yeast. We know that a certain portion of alcohol destroys fermentation. Thus, we have found, by a great many trials, conducted on rather a large scale, that the stronger a wort is made, the greater is the quantity of unaltered saccharine matter which remains in it after the fermentation has been carried to the greatest possible length. Hence the present mode of levying the duties on spirits upon the wash is not only very injurious to the goodness of the spirits manufactured, but is attended with a positive and very heavy loss to the community. Distillers' wash may be fermented a second time, and would, in this way, yield a considerable additional quantity of spirits. We have frequently seen it made into good small beer. The proper mode of levying the duty would be on the quantity of saccharine matter in the wash. This might easily be determined by a good saccliarometer. A certain part of the duty might likewise be levied upon the spirits produced. This would act as a sort of check upon the first esti mate, and would considerably diminish the risk of fraud. Indeed, the mode of determining the duty ' by the quantity of saccharine matter, would not be more liable to evasion than the present mode. It could be evaded in no other way than by concealing a portion of the wash, which would be equally efficacious according to the present mode.
We conceive, therefore, that when yeast is mixed with alcohol, it may retain so much of that liquor as " to prevent it from acting as a ferment. When we attempt to wash away the alcohol, we may destroy the yeast by washing away that portion of it which really acts as a ferment, which is probably small in quantity.
It seems to us not unlikely, that the portion of yeast which really acts as a ferment, is a quantity of saccharine matter which it contains, that has begun to undergo the decomposition produced by fermentation, but has not yet completed the change. For nothing more seems to be necessary than to begin the fermentative process in wort; the process then goes on of itself. It would be curious to know whether a high temperature (96° or 100°) might be substituted in distilleries for the great quantities of yeast afr present employed. We believe that the reason why such great quantities of yeast are necessary in distilleries, is the very great strength of the wash employed; as they are obliged by law to produce a quantity of proof spirits, amounting nearly to one-fifth of the whole bulk of the wash. Nothing can be more preposterous than such a method, nor more contrary to the real interest of the community, which obviously must be to produce the greatest quantity of good spirits from a given quantity of grain.
The quantity of yeast mixed with the wort in "the fermenting-tuns by brewers is very small, amounting, at an average, to a gallon of yeast for every three barrels of wort. The following table will give the reader an idea of the quantities of yeast really mixed by the Edinburgh brewers with their strong-ale worts in different brewings. It is obvious, however, that the quantity of yeast must be regulated in some measure by its goodness.
Quantity of Wort in Barrels.
Lbs. per Barrel of Saccharine Matter.
Quantity of Yeast added in Gallons.
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