This article is from the Food Preserving FAQ, by Eric Decker email@example.com with numerous contributions by others.
Pickling food encompasses several techniques, but usually involves
equilibrating food in a salt solution, then one either adds an acid
(vinegar), or allows the growth of free yeasts and bacteria to make
lactic acid by fermentation. If you are trying to pickle food using
fermentation, you need to insure that the salt concentration in your
crock will support the microbes you need, and you need to control and
monitor their growth. Since you are working with a salt and acid, you
also want to make sure that you pickle in a non-reactive container
(e.g. porcelain, glass). ----
PICKLES AND FERMENTED PRODUCT SAFETY
From Susan Brewer, files at the cesgopher.ag.uiuc.edu
The acidity (pH) of a food is of great significance in determining the
type of processing required for safe preservation of a food. In the
case of pickled products, the foods preserved are often low-acid foods
(cucumbers, zucchini), but their acidity is adjusted to bring the pH
into the high-acid range so that may be safely preserved using boiling
water bath processing.
The most commonly used acid for pickling is vinegar, however some
pickle products are produced by encouraging the growth of
microorganisms which produce lactic acid from the naturally occurring
carbohydrates in fruits and vegetables. The lactic acid selects for
another group of microorganisms which produce acetic acid that gives
pickle products their flavor and helps to lower the pH into the range
where these vegetables can be safely water bath canned.
The acidity of pickling solutions needs to be maintained below pH 4.5
if water bath canning is to be used. For this reason, the amount and
strength of the vinegar is critical.
I. Types of Pickles
o A. Brined or fermented: Depends on selection of natural micro-
organisms which will produce acid. Selection is accomplished by
using salt to inhibit unwanted microbes. Fermentation is usually
for 3 weeks or more. Color changes from bright green to olive or
yellow green and white interior becomes translucent. Examples:
sour pickles, sauerkraut.
o B. Refrigerator dills: are fermented for one week.
o C. Fresh-pack or quick-process pickles: Cured for several hours
or combined immediately with hot vinegar, spices and seasonings.
Examples: pickled beets, bread and butter pickles.
o D. Fruit pickles: Whole or sliced fruit simmered in a spicy,
sweet-sour syrup. Examples: spiced peaches, crabapples.
o E. Relishes: Made from chopped fruits or vegetables which are
cooked to desired consistency in a spicy vinegar solution.
Examples: horseradish, corn relish.
o F. Pasteurized Pickles: Prepared pickles are placed in a canner
half filled with warm (120-140 F) water. Add hot water to 1" over
jar lids. The water is then heated to 180-185 F and maintained
there or 30 minutes. Temperatures over 185 F may cause softening
USE THIS PROCEDURE ONLY WHEN THE USDA CANNING GUIDELINE RECIPES
o A. Vegetables or fruits for pickling
+ 1. Fruits and vegetables should be ripe but firm, and in
good condition with no evidence of microbial or insect
+ 2. Cucumbers should have a 1/16" slice removed and discarded
from the blossom end.
+ 3. Use unwaxed cucumbers for pickling so brine will
+ 4. Discard any cucumbers which "float"--they can make hollow
pickles (use for relish).
+ 5. Prepare fruits and vegetables within 24 h of harvest.
+ 6. Cucumbers: need 14 lb for 7 quart canner load, 9 lb per 9
pint canner load. One bushel weighs 48 lb and yields 16-24
quarts (2 lb / quart). Use 1 1/2" for gherkins and 4" for
o B. Vinegar
+ 1. Vinegar needs to be of sufficient strength to assure that
low-acid vegetables will be appropriately acid. The vinegar
should be 5 to 6% acetic acid (50 to 60 grain), and should
not be diluted except according to an approved recipe.
+ 2. White vinegar is preferred with light colored fruits or
+ 3. Do not use homemade vinegar--there is no way to know the
strength (% acetic acid).
o C. Salt
+ 1. Canning or pickling salt should be used--it contains no
iodine (which can cause darkening) or anti-caking
ingredients (sodium silicate or tricalcium phosphate) (which
cause cloudiness of the brine).
+ 2. Salt inhibits certain kinds of microorganisms and in
fermented pickle products, it is required to prevent growth
of spoilage and pathogenic microorganisms. Salt also draws
water out of the cells making the pickled product more firm.
Too much salt will cause shriveling.
+ 3. Do not use "sour salt"--it is citric acid and does not
have the same inhibitory effect on microbes.
+ 4. Do not use reduced-sodium salt in fermented pickle
recipes. Reduced sodium pickles can be made using quick
pickle recipes given in the USDA Canning Guidelines. Fresh
pack pickles, acidified with vinegar can be prepared with
little salt but the flavor and texture will be affected.
+ 5. Salt concentration in brined, fermented products must not
be reduced for safety. Do not try to make sauerkraut or
fermented pickles by cutting down on the salt.
o D. Sugar
+ Either white or brown granulated sugar can be used.
o E. Spices
+ 1. Use fresh, whole spices in cheesecloth bag.
+ 2. Powdered spices cause darkening and clouding.
o F. Hard Water
+ 1. Hard water minerals may interfere with acid formation and
curing in fermented pickles. In addition, hard water may
have a pH of 8.0 or higher.
+ 2. Softening hard water: boil water for 15 minutes then
allow to stand for 24 hours. Skim off any scum that appears.
Pour out of container so sediment is not disturbed.
o G. "Crisping Agents"
These products are not recommended as they may result in a
product with a pH which is unsafe.
+ 1. Lime (calcium hydroxide) which is sold as "slakelime",
"hydrated lime", "builders lime", or "household lime". When
called for in a recipe, it is added to the brine before
pickles are soaked. When used, lime is added for 12-24 hours
of soaking. It must be removed from pickles by soaking (1
hour) and rinsing three times in fresh water in order to
make the pickles safe. The component of calcium hydroxide
which firms up the pickles is the calcium--it cross-links
the pectins making them insoluble.
DO NOT USE: agricultural lime, burnt lime, quick lime--these
are not food grade products and are unsafe.
+ 2. Alum (aluminum and potassium sulfates): Use no more than
1/4 tsp of alum per quart of pickling solution. Excess will
cause bitterness. Alum may be safely used--it does not
improve the firmness of quick-process pickles.
+ 3. Grape leaves: contain substances which inhibit enzymes
that make pickles soft. Blossom removal takes care of this
+ 4. Hot process: pickle firmness may be improved by
processing the pickles for 30 minutes in water maintained at
180 F. Water must not fall below 180 F--prevents spoilage
Prepared by Susan Brewer/Foods and Nutrition Specialist/Revised,
1992 EHE-696 ----