[4] When vinegar is used, the equivalent sugar hydrometer reading would be about 2 degrees higher than that indicated in the table.
Table 4.—Number of cucumbers of various sizes required to make a gallon of pickles
| Size | Variety | Number to a gallon |
| 1 to 2 inches long | Gherkins[5] | 250 to 650 |
| 2 to 3 inches long | Small pickles | 130 to 250 |
| 3 to 4 inches long | Medium pickles | 40 to 130 |
| 4 inches and longer | Large pickles | 12 to 40 |
[5] Small pickles are usually designated as gherkins. Those of very small size are sometimes called midgets.
The maximum acidity formed by a lactic fermentation of vegetables in brine varies from 0.25 to 2 per cent. The maximum is reached at or soon after the close of the active stage of fermentation. After this the acidity usually decreases slowly. The stage of active fermentation continues for from one to three weeks, depending upon the temperature, strength of brine, etc. During this period gas is formed and froth appears on the surface, owing to the rising of gas bubbles. At the close of this period the brine becomes "still."
The quantity of acid formed depends primarily upon the sugar content of the vegetables fermented, but it may be influenced by other factors.
Dipping a piece of blue litmus paper (obtainable at drug stores) in the brine will show whether the brine is acid. If the paper turns pinkish or red, the brine is acid, but the litmus paper does not give a definite indication of the degree of acidity.
For those who want to know accurately what the degree of acidity is the following method is outlined:
With a pipette transfer exactly 5 cubic centimeters of the brine to a small evaporating dish. To this add 45 cubic centimeters of distilled water and 1 cubic centimeter of a 0.5 per cent solution of phenolphthalein in 50 per cent alcohol. Then run in slowly a one-twentieth normal sodium hydrate solution. This is best done by using a 25 cubic centimeter burette, graduated in tenths. As the sodium hydrate is being added stir constantly, and note carefully when the entire liquid shows a faint pink tint. This indicates that the neutral point has been reached. Read off carefully the exact quantity of sodium hydrate required to neutralize the mixture in the dish. This number multiplied by 0.09 gives the number of grams of acid per 100 cubic centimeters, calculated as lactic, present in the brine.
This method can be used to determine the acid strength of vinegars. Multiply by 0.06 to ascertain the number of grams of acetic acid per 100 cubic centimeters present in the vinegar.
The apparatus and chemicals needed for this test can be obtained from any firm dealing in chemical apparatus and supplies.
ORGANIZATION OF THE UNITED STATES DEPARTMENT OF AGRICULTURE
| Secretary of Agriculture | Henry C. Wallace. | |
| Assistant Secretary | Howard M. Gore. | |
| Director of Scientific | Work E. D. Ball. | |
| Director of Regulatory Work | Walter G. Campbell. | |
| Director of Extension Work | C. W. Warburton. | |
| Solicitor | R. W. Williams. | |
| Weather Bureau | Charles F. Marvin, Chief. | |
| Bureau of Agricultural Economics | Henry C. Taylor, Chief. | |
| Bureau of Animal Industry | John R. Mohler, Chief. | |
| Bureau of Plant Industry | William A. Taylor, Chief. | |
| Forest Service | W. B. Greeley. Chief. | |
| Bureau of Chemistry | C. A. Browne, Chief. | |
| Bureau of Soils | Milton Whitney. Chief. | |
| Bureau of Entomology | L. O. Howard, Chief. | |
| Bureau of Biological Surrey | E. W. Nelson, Chief. | |
| Bureau of Public Roads | Thomas H. MacDonald, Chief. | |
| Bureau of Home Economics | Louise Stanley. Chief. | |
| Bureau of Dairying | C. W. Larson, Chief. | |
| Office of Experiment Stations | E. W. Allen. Chief. | |
| Fixed Nitrogen Research Laboratory | F. G. Cottrell, Director. | |
| Publications | L. J. Haynes, In Charge. | |
| Library | Claribel R. Barnett. Librarian. | |
| Federal Horticultural Board | C. L. Marlatt, Chairman. | |
| Insecticide and Fungicide Board | J. K. Haywood. Chairman. | |
| Packers and Stockyards Administration | } | Chester Morrill, Assistant to the Secretary. |
| Grain Futures Administration | ||
This bulletin is a contribution from
Bureau of Chemistry C. A. Browne, Chief.
Microbiological Laboratory Charles Thou, Mycologist in Charge.
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Transcriber Notes
Figure 1 was moved so that it would not split a paragraph.