A Guide To The Scientific Knowledge Of Things Familiar Part 60

Q. _Why is BARLEY MALTED?_

A. Because _germination_ is produced by the artificial heat; and in germination the _starch of the grain_ is converted into _sugar_.

Q. _How is barley malted?_

A. The barley is _moistened with water_, and _heaped up_; by which means, great _heat_ is produced, which makes the _barley sprout_.

Q. _Why is not the BARLEY suffered to GROW, as well as SPROUT?_

A. Plants in the _germ_ contain _more sugar_ than in any _other state_; as soon as the germ _puts forth shoots_, the _sugar_ of the plant is _consumed_, to _support the shoot_.

Q. _How is BARLEY PREVENTED from SHOOTING, in the process of MALTING?_

A. The barley is _put into a kiln_ as soon as it sprouts; and the _heat_ of the kiln checks or _destroys the young shoot_.

Q. _Why is YEAST put into BEER to make it WORK?_

A. Yeast supplies the beer with _nitrogen_, which is one of the ingredients of alcohol.

Alcohol consists of _oxygen_, _carbon_, and _hydrogen_, (obtained from the sugar of malt), and _nitrogen_, (obtained from yeast).

Q. _Why is it NOT needful to put YEAST into WINE?_

A. Because fruit contains _carbon_, _hydrogen_, _oxygen_, and _nitrogen_, in the form of "gluten;" and, therefore, ferments _spontaneously_.

(Gluten is explained fully in the Appendix.--Turn to the word in the Index.)

Q. _Does not MALT contain carbon, hydrogen, oxygen, and nitrogen, as well as FRUIT?_

A. No; the sugar of malt contains _carbon_, _hydrogen_, and _oxygen_, but _no nitrogen_; in consequence of which, _yeast_ (which contains _nitrogen_) is _added to the wort_.

Q. _Why do NOT GRAPES ferment while they hang on the VINE?_

A. 1st--Because the skin lets out the _water of the pulp_, which causes the grapes to shrivel and dry up: and

2ndly--The skin _prevents_ the admission of _oxygen into the pulp_, from the air without.

Q. _What is the FROTH or Sc.u.m of fermented LIQUORS?_

A. _Carbonic acid gas_, which (being heavier than common air) _settles on the top of the liquor_, in the form of sc.u.m.

Q. _Why does a small piece of raw MEAT, or a few RAISINS improve FLAT BEER?_

A. 1st--Because they supply it with _nitrogen_ to form it into al'cohol.

2ndly--As the raw meat, &c. _putrifies_, it gives off _carbonic acid gas_ into the beer, which gives it "life."

Q. _Why is BEER FLAT, if the cask be open too long?_

A. Because _too much of the carbonic acid gas_ (produced by fermentation) is suffered to _escape_.

Q. _How is the CARBONIC ACID GAS of BEER generated?_

A. The saccharine (or sugar) of the malt is converted by _fermentation_ into carbonic acid gas and alcohol.

Q. _Why does BEER turn FLAT, if the VENT PEG be left OUT of the tub?_

A. Because the _carbonic acid gas escapes_ through the vent hole.

Q. _Why will NOT beer RUN OUT of the tub, till the VENT PEG is taken out?_

A. When the tap is turned, _air rushes through the tap_ into the bottom of the tub, and _holds the liquor in_.

The _upward_ pressure of air is ill.u.s.trated by the

following simple experiment:--Fill a wine-gla.s.s with water; cover the top of the gla.s.s with a piece of writing paper; turn the gla.s.s topsy turvy, and the water will not run out. The paper is used merely to give the air a medium sufficiently dense to act against.

Q. _Why does the BEER RUN FREELY, immediately the VENT PEG is taken out?_

A. As soon as the vent peg is taken out, air rushes _through the vent hole_ at the _top of the tub_,--presses the liquor _down_, and _forces it through the tap_.

Q. _Why does liquor flow reluctantly out of a BOTTLE held upside down?_

A. Because the _upward pressure of the air_ prevents the liquor from flowing out.

Q. _Why should a bottle be held OBLIQUELY, in order to be emptied of its liquor?_

A. Because _air_ will then _flow into the bottle_, and help the liquor out by _balancing the upward pressure_.