In addition to bacteria, yeasts are present in the brine; but because they
need oxygen they grow principally on the surface. The scum yeast feed
on the acid of the brine and decompose it, thus decreasing the quantity of
acid in the tank or container. If scum grows long enough, all the acid is
destroyed and then the pickles become slippery, soft, and mushy. It is better
not to stir the pickles too much after they are in the brine, for the acid
tends to stay at the bottom of the container and the yeasts grow at the
surface.
EFFECT OF SUGAR ON THE FIRMNESS OF FRUIT 131
There are two periods when the acid is low, and these stages are the
periods of greatest danger in fermenting pickles. The first stage is before
fermentation has started and no or little acid has been formed ; the second
is after the acid has been used up by scum yeast, for spoilage only occurs
when the acidity of the brine is sufficiently low. The slipperiness and soft-
ness are caused by so-called potato bacteria, which resist the salt well
but do not tolerate acid. Because oxygen is necessary for their growth and
the bacteria only grow at the surface, the pickles protruding from the brine
become soft. These potato bacteria can cause great loss and damage before
a concentration of acid great enough to delay their growth is formed.
A single potato bacterium, if all conditions are favorable, produces from
10 to 100 million new bacteria in 24 hours.
Hence, to prevent spoilage all pickles should be kept under the brine.
Some acid or vinegar can be added with the brine to prevent spoilage.
It has been interesting to see that this has been advocated for commercial
practise since Rahn's work was published. Other methods of preventing
growth of the yeast are to keep the container in the sunlight or irradiate
with ultra-violet light, both of which are not practical in the home. After
fermentation is complete, that is, after frothing has ceased, oil or paraffin
may be used over the surface of the brine. Since the oil is rather difficult
to wash from the pickles, paraffin is preferable.
Crisping pickles. Calcium chloride is used to make pickles crisp or firm.
It is used either in the last soaking water, when the brine is being removed,
or added directly to the sweetened vinegar. The proportion used is one
pound per barrel of pickles.
The hardening may come from the calcium combining with the cellulose
or it may combine with acid of the pickle or melon or be deposited as
calcium salts in the food. Some factors other than the ones mentioned may
cause the hardening.
Page 105
Presented as published in 1932. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
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In addition to bacteria, yeasts are present in the brine; but because they
need oxygen they grow principally on the surface. The scum yeast feed
on the acid of the brine and decompose it, thus decreasing the quantity of
acid in the tank or container. If scum grows long enough, all the acid is
destroyed and then the pickles become slippery, soft, and mushy. It is better
not to stir the pickles too much after they are in the brine, for the acid
tends to stay at the bottom of the container and the yeasts grow at the
surface.
EFFECT OF SUGAR ON THE FIRMNESS OF FRUIT 131
There are two periods when the acid is low, and these stages are the
periods of greatest danger in fermenting pickles. The first stage is before
fermentation has started and no or little acid has been formed ; the second
is after the acid has been used up by scum yeast, for spoilage only occurs
when the acidity of the brine is sufficiently low. The slipperiness and soft-
ness are caused by so-called potato bacteria, which resist the salt well
but do not tolerate acid. Because oxygen is necessary for their growth and
the bacteria only grow at the surface, the pickles protruding from the brine
become soft. These potato bacteria can cause great loss and damage before
a concentration of acid great enough to delay their growth is formed.
A single potato bacterium, if all conditions are favorable, produces from
10 to 100 million new bacteria in 24 hours.
Hence, to prevent spoilage all pickles should be kept under the brine.
Some acid or vinegar can be added with the brine to prevent spoilage.
It has been interesting to see that this has been advocated for commercial
practise since Rahn's work was published. Other methods of preventing
growth of the yeast are to keep the container in the sunlight or irradiate
with ultra-violet light, both of which are not practical in the home. After
fermentation is complete, that is, after frothing has ceased, oil or paraffin
may be used over the surface of the brine. Since the oil is rather difficult
to wash from the pickles, paraffin is preferable.
Crisping pickles. Calcium chloride is used to make pickles crisp or firm.
It is used either in the last soaking water, when the brine is being removed,
or added directly to the sweetened vinegar. The proportion used is one
pound per barrel of pickles.
The hardening may come from the calcium combining with the cellulose
or it may combine with acid of the pickle or melon or be deposited as
calcium salts in the food. Some factors other than the ones mentioned may
cause the hardening.