BEER 305 



sour at a temperature from 149 to 167. It has the property of converting starch 

 into gum, or dextrine (so called by the French chemists, from its polarising light to 

 the right hand, whereas common gum does it to the left) and sugar ; and, indeed, 

 when sufficiently pure, the diastase operates with such energy that one part of it dis- 

 poses 2,000 parts of dry starch to that change, but it operates the quicker the greater 

 its quantity. 



Whenever the solution of diastase with starch is heated to tho boiling point, it loses 

 the converting property. 



One hundred parts of the starch solution from good malt appear to contain about 

 one part of this substance, which is of the greatest importance in effecting the further 

 changes which take place in the process of brewing. 



3. THE FORMATION OF A SACCHABINE LIQUID, OB WOET, 



from the inalt and hops, and production of the finished beer, is the province of the 

 brewer ; and the process will be found at length under the article BREWING. 



The peculiar properties contained in wort do not exist ready formed in malt, but 

 are the result of the joint action of water and heat which is employed in the initiatory 

 process of the brewer on that substance, and is termed the mashing. 



The Mashing. This operation requires the greatest care, as on it, almost as much 

 as on the malt employed, depends the character of the liquor. 



Payen and Persoz, already alluded to, show that the mucilage formed by the reaction 

 of malt upon starch may be either converted into sugar or be made into a permanent 

 gum, according to the temperature of the water in which the materials are digested. 

 We take of pale barley-malt, ground fine, from 6 to 10 parts, and 100 parts of starch ; 

 we heat, by means of a water-bath, 400 parts of water in a copper to about 80 F. ; we 

 then stir in the malt, and increase tho heat to 140 F., when we add the starch, and 

 stir well together. We next raise the temperature to 158, and endeavour to maintain 

 it constantly at that point, or, at least, to keep it within the limits of 167 on the one 

 side and 158 on the other. At the end of twenty or thirty minutes the original milky 

 and pasty solution becomes thinner, and soon after as fluid nearly as water. This is 

 the moment when the starch is converted into gum or dextrine. If this merely 

 mucilaginous solution, which seems to be a solution of gum with a little liquid starch 

 and sugar, be suitably evaporated, it may serve for various purposes in the arts to 

 which gum is applied ; but, with this view, it must be quickly raised to the boiling 

 point, to prevent further change. If we wish, on the contrary, to produce a sac- 

 charine fluid, such as the wort for beer, we must maintain the temperature at be 

 tween 158 and 167 for three or four hours, when the greatest part of the starch 

 will have passed into sugar, and by evaporation of the liquid at the same temperature, 

 a starch syrup may be obtained like that procured by the action of sulphuric acid 

 upon starch. 



In the operation of mashing, the finished and mellowed malt, having been well 

 cleansed from all extraneous matters by screening, is coarsely ground, or better if 

 only crushed between iron rollers, as is now generally practised. It is then gradually 

 mixed with water in the mash-tun, at the proper heat, and intimately blended by 

 stirring with the mashing-rakes, so that it may be uniformly moistened and no lumps 

 remain. After being allowed some time to stand and settle, the liquor is drawn off, 

 and more water at a higher temperature is added, again intimately blended with the 

 malt now termed the ' goods ' again allowed to rest, and drawn off; the operation 

 being repeated until the complete exhaustion of the saccharine and amylaceous sub- 

 stances of the malt is effected. 



We can now see, from Payen and Persoz's experiment just given, the. temperature 

 at which the liquor ought to be maintained in this operation ; namely, the range 

 between 158 and 167 ; and it has been ascertained, as a principle in mashing, that 

 tho best and soundest extract of the malt is to bo obtained, first, by beginning to work 

 with water at the lowest of these heats, and to conclude with water at the highest ; 

 secondly, not to operate the extraction at once with the whole of the water that is to 

 be employed, but with separate portions and by degrees. 



The first portion has the task of penetrating equally the crushed malt, extracting 

 the more soluble ingredients and subjecting the dissolved starch to the action of the 

 diastase and free sugar ; the second and further portions are for the purpose of con- 

 verting the remaining starch and completing tho extraction of all tho available pro- 

 ducts. By this means also the starch is not allowed to run into a cohesive paste, or, 

 as it is termed, lock up tho goods,' and the extract is more easily drained from the 

 mass, and comes off a nearly limpid wort. The thicker, moreover, or the less diluted 

 the mash is, so much the easier is the wort fined in the boiler or copper by the coagu- 



X 



