Page:A Practical Treatise on Brewing (4th ed.).djvu/230

214 stated to me that there is no such thing as diastase as a distinct principle.

Of its actual effects in the mash-tun, we know very little more than when it was first discovered, being merely that some peculiar change is effected in barley in the process of malting, without which but very little saccharine extract can be obtained. Corn-distillers also cannot get an extract without a mixture of malt.

We know also that a certain temperature is requisite to be acquired in the mash-tun before the extract can be thoroughly formed, and that going beyond this temperature may do harm, but cannot be of any beneﬁt. When the proper temperature is gained, an almost instantaneous change takes place in the appearance of the mash, so perceptible to any one at all acquainted with the process as fully to point out to him that his object is now attained. He also knows that very little further manipulation on his part is either useful or beneficial—and I can assure him that a few degrees up or down in the temperature of the mash, when running off from the tun (upon which so much is sometimes thought to depend) will be of no material importance. He may be certain that the proper chemical change has taken place for ultimately producing the best beer; let him not then, by a mistaken avarice, in carrying the process too far, run the risk of counteracting, by any addition of that which