ALMOST every one who has made brine pickles has had the maddening experience of having them turn soft. In factories this has caused much loss of money - in Michigan, for example, the loss from this cause is estimated at an average of about $1,000 a year for each factory; in homes it has caused much loss of labor and temper, for what is true of the factory's tank in regard to pickle softening is just as true of the housewife's two-gallon crock. The difference is that whereas the factory has been able to carry on expensive investigations into the cause of pickle spoilage, the housewife could only hope for better luck next year. Now, however, the time has come when the housewife can, if she will, make use of the factory's knowledge.

Investigations of especially noteworthy thoroughness have been made by Dr. Otto Rahn, who is in charge of the canners' fund of the University of Illinois. His work occupied a period of six months; but as six calendar months mean three pickle years practically every characteristic of the conditions likely to be met with in brine pickling is covered thereby. Dr. Rahn, setting out to understand the normal brine pickle from the very beginning, first ascertained just what happens to a cucumber to change it into a pickle. In this connection, he discovered one very interesting fact: it is not the salt in the brine that causes the pickle to keep. Salt, and that in good measure, is absolutely necessary to pickle keeping, but salt alone is not enough. The essential factor in keeping brine pickles is the acid, probably lactic acid, which forms through the action of bacteria. Many manufacturers do not know that their brine contains acid, yet the instant it does not contain it the pickle is on the way to destruction.

There are no bacteria in a healthy cucumber, nor are there any in strong brine; then how do they get into the pickle-tank? They ride in in thousands on the outside of the cucumber, especially if a little soil adheres. Immersion in strong brine finishes the life story of most of them, but a few regard it as a chance to prove themselves. And from within the cucumber comes their food. The cucumbers shrink in the brine, giving off water, and with It sugar, and other traces of bacterial food. Sugar is especially acceptable to the busy bacteria, and the kinds that can tolerate the salt immediately begin to grow and decompose the sugar. Acid and gas follow upon this decomposition. The gas escapes and makes the familiar froth, while the acid reveals its presence by its action upon the color of the pickles, turning their grass-greenness to the olive-green everywhere recognized as the correct tint for pickles. When the frothing ceases, the acid becomes fairly strong, and as it is a rather capable disinfectant, it will kill most of the bacteria in the brine.

But the trouble is, that there is more than just this acid formed in the brine. The brine and the cucumbers in combination possess not alone the power of establishing their own preservation, but also the power of bringing about their own destruction. Besides the bacteria, a skum-yeast is always present in the brine. This skum-yeast destroys the lactic acid, and leaves the pickles open to destruction. Were the growth of this skum-yeast prevented so that the acid would remain in the brine, pickles undoubtedly could be kept for centuries.

But the encouraging fact brought by the investigations is that the prevention of skum-yeast is not impossible or even excessively difficult. Skimming it off is an inefficient and unsatisfactory method of getting rid of it, because it always grows in again; but it cannot tolerate sunlight, and it must have air. The old-fashioned outdoor tanks were not bothered much with skum-yeast; trouble started when the roof was built. As for the necessity of air to skum-yeast, that is attested by the very fact that it grows as a skum. On the other hand, the bacterium which forms the acid in the brine has just the opposite characteristic - it avoids the air. Sunlight, too, would kill it, but it grows at the bottom of the tank, or jar, where there is no light. So it becomes apparent that whatever shuts the air from brine pickles encourages the presence of acid, and also discourages the skum-yeast.

Dr. Rahn's experiments proved this point very clearly. He experimented with pickles in glass jars and also in barrels, with precisely similar results. In the case of the barrels, six barrels of cucumbers were brined in the usual way; then three of them were kept open, while the other three were covered with about two inches of cottonseed oil, after the barrels were headed up, air-tight, with but one small hole for the gas to escape. All six barrels fermented normally, but at the end of twenty-two months the pickles in the three open barrels were so soft that they could not be taken out without falling to pieces, while those in the closed barrels were in first-class condition and of excellent flavor. The brine of the open barrels showed no trace of acid, in fact, it was slightly alkaline, while the brine under oil had not changed its acidity in twenty-one months. Do not, however, suppose from this that cottonseed-oil is the essential of preservation. What is to be recommended is the exclusion of air.

Indeed, cottonseed-oil cannot be used by manufacturers or housewives, because it would make the pickles oily, and eventually rancid. There is, however, paraffin, that noble ally of the jelly-jar. This gave complete satisfaction when tried on a two-gallon jar of pickles; and even in factories its use would not be too expensive, as the paraffin could be remelted and used year after year. But of course, in case of its use, care must be taken not to pour it on until the fermentation has ceased, as otherwise the gases arising from the brine would tear it to pieces and make a remelting necessary. But the great fact is that exclusion of air will result in the retention of the acid and the prevention of the formation of the skum-yeast which destroys the acid, thus causing the pickles to keep indefinitely.

There is also an earlier stage in the life history of a pickle, when certain bacteria can get in their work of destruction, and should consequently be guarded against. This is the period before normal fermentation begins. In Dr. Rahn's opinion, the spoilage that may then occur is due to the action of one of the so-called potato bacteria. These stand salt well, and if they happen to be present in fairly large numbers, they can do great damage, for they grow very fast. Fighting these bacteria, however, is not difficult. Putting in brine from a fermenting tank or jar, or even a little vinegar, will speedily cause their career to cease. Where this is not possible, attention to temperature and whatever induces rapid fermentation will put them out of the ranks of troublemakers.. Also, pickles should be compelled to stay under brine instead of being allowed to poke out where the potato bacteria can catch them.

In short, the great secret of successful pickle-making lies in bringing about acid fermentation quickly, and after this is over, in preserving the acidity of the brine.

Since some bacteria are necessary for the keeping of pickles, it is not advisable to rid the outside of the cucumbers of bacteria before putting them into brine, for then the good would perish with the evil bacteria. Neither is it necessary to wash the cucumbers, since all brine pickles are washed anyway before being eaten. In the case of dill pickles, of course, this does not apply. They are eaten as they come from the tank, and therefore the cucumbers used in making them should be washed before pickling. It has been recommended by a German bacteriologist that a little whey from sour milk be put into the pickle-barrel to hasten the fermentation. But this practice has been tried with dill pickles only - brine pickles being unknown in Germany.