It tends to destroy insects and weeds, and gets rid of acidity of the soil.
At the same time the acidity is markedly reduced.
At the end of the melting down, dephosphorization is then impeded by the temporary acidity of the slag, as just explained.
This reduction of acidity is partly due to the deposition of various salts of tartaric acid, which are less soluble in a dilute alcoholic medium than in water, and partly to the action of micro-organisms. Young wines differ very widely in their composition according to class and vintage.
At the same time, their acidity is very low and their bouquet characteristically delicate and elegant.
It is found that transparent oils under the influence of light absorb oxygen, becoming deeper in colour and opalescent, while strong acidity and a penetrating odour are developed, these changes being due to the formation of various acid and phenylated compounds, which are also occasionally found in fresh oils.
In 1780 he proved that the acidity of sour milk is due to what was afterwards called lactic acid; and by boiling milk sugar with nitric acid he obtained mucic acid.
After absorption into the blood, the acetates are oxidized to carbonates, and therefore are remote alkalies, and are administered whenever it is desired to increase the alkalinity of the blood or to reduce the acidity of the urine, without exerting the disturbing influence of alkalies upon the digestive tract.
A slight degree of acidity seems more favourable to the crystallization of salt than alkalinity; thus it is a practice to add a certain amount of alum, 2 to 12 lb per pan of brine, especially when, as in fishery salt, fine crystals are required.
When the grape is ripe, the sugar has attained to a maximum and the acidity is very much reduced; the tannin has entirely disappeared.
The acidity may vary between 0.3 and 1% according to circumstances.
It is principally due to a lack of alcohol in the wine cr to lack of acidity in the must.
It will be seen that, compared with the dry, light red wines, the proportion of sugar, alcohol and acidity is comparatively high in champagne, and the extract (solid matter) rather low.
Hence the composition and acidity of the solution, on which so much depends, must be constantly watched.
A perfect soil would be such a blend of sand, clay, chalk and humus as would contain sufficient clay and humus to prevent drought, enough sand to render it pervious to fresh air and prevent waterlogging, chalk enough to correct the tendency to acidity of the humus present, and would have within it various substances which would serve as food-materials to the crops.
The method introduced by Dyer of dissolving out the mineral constituents of the soil with a i% solution of citric acid, which represents about the average acidity of the roots of most common plants, yields better results.
He carried the humour and sub-acidity of discrimination which marked his criticism of fellow folk-lorists into the discussion of purely literary subjects in his Books and Bookmen (1886), Letters to Dead Authors (1886), Letters on Literature (1889), &c. His Blue Fairy Tale Book (1889), beautifully produced and illustrated, was followed annually at Christmas by a book of fairy tales and romances drawn from many sources.
The character of the acidity, however, changes, the free tartaric acid gradually disappearing, forming bitartrate of potash and being otherwise broken up. On the other hand, the free malic acid increases and the tannin decreases.
The fact is that the constitution of average grape juice and the temperatures of fermentation which generally prevail are particularly well suited to the life action of wine yeast, and are inimical to the development of the other organisms. When these conditions fail, as is, for instance, the case when the must is lacking in acidity, or when the weather during the fermentation period is very hot and means are not at hand to cool the must, bacterial side fermentations may, and do, often take place.
As the wine matures the most noticeable feature in the first instance is the reduction in the acidity, which is mainly due to a deposition of tartar, and the disappearance of tannin and colouring matter, due to fining and the action of oxygen.
As a rule, wines which are kept for many years in cask become very dry, and the loss of alcohol by evaporation - particularly in the case of light wines - has as a result the production of acidity by oxidation.
It has been found, for instance, that in the case of the mannitic disease the action of the micro-organism may be checked, or prevented altogether, by bringing the acidity of the must up to a certain level by the addition of a small quantity of tartaric acid.