Michigan State University Extension
Preserving Food Safely - 01600611
10/13/97
1. Dark (gray or brown) Pickles Darkness in pickles may be caused by:
Use of ground spices or too much spice.
Packing whole spices in jars with pickles. Whole cloves, allspice, cinnamon should only be used to flavor the pickling liquid.
Iodized salt.
Corrosion of metal lids.
Minerals in the water, especially iron.
A silver fork is recommended for piercing brined cucumbers to desalt them. While an iron fork should not be used, stainless steel is acceptable.
Darkened pickles are not attractive but they are safe to eat.
2. Blue Garlic
Pickle recipes sometimes call for several cloves of raw
garlic. Raw garlic contains an active enzyme system that
may remain active if jars are sealed without processing
(processing is recommended for ALL shelf stable canned
goods). Garlic also contains sulfur compounds. In the
presence of a little copper, the enzymes may catalyze a
reaction between the copper and the sulfur to form copper
sulfate, a blue compound. The amount of copper required
for this reaction is very low and is frequently found in
normal water sources. It is unlikely that any health hazard
is involved.
3. Green Garlic
If garlic is not fully mature or thoroughly dry, it may
turn green. This discoloration is due to a reaction between
the acid in the vinegar and the pigment in the garlic. It
is harmless.
4. Red Brine
Rust often causes red brine. Determine if the water
lines had been flushed out shortly before the pickles
were made. If so, there is a possibility that water
containing a little rust was used for the brine. Store the
pickles, undisturbed for a few months; the red color will
usually disappear.
5. Pink or Red Dill
Pink discoloration in dill is due to a change in the
structure of pigment compounds which are normally colorless.
It is harmless.
6. Pink of Gray Cauliflower
Pink discoloration in cauliflower is due to a change in
the structure of pigment compounds which are normally
colorless. In the presence of a little iron these pigment
compounds may be converted to forms which are gray. Avoid
iron contamination during all stages of preparing pickled
cauliflower. Pink or gray discoloration may be minimized by
blanching the florets for 3 minutes in boiling water
containing 2 to 3 tablespoons of lemon juice per gallon.
These discolorations are harmless.
7. Dark Pickled Cauliflower, Onions, Pears, etc.
Cider vinegar may darken white or light-colored
vegetables and fruits. White distilled vinegar is desirable
when light color is important. The darkening is harmless.
8. Pink or Dark Sauerkraut
Undesirable color, off-odors and soft texture indicate
spoilage in sauerkraut. DO NOT USE THE SAUERKRAUT.
9. Dirty Pinkish Gray Sauerkraut Made From Red Cabbage
Unless iron contamination is completely avoided (and
for all practical purposes this is impossible in the home),
sauerkraut made from red cabbage will turn a dirty pinkish
gray. The kraut is unattractive but safe to eat provided
that there is no evidence of spoilage (e.g. soft texture,
off-odors, off-flavors, mold growth).