Frugal Kitchens 101 - A Few Harmless Home Canning Anomalies

We are in the midst of the busiest canning for the year.  This means the canners are running as much as four times a day.  New home canners often panic when they see a colour change in their home canned product.  Now, the rule of thumb is always if in doubt, throw it out but some colour changes are completely harmless.  Fruits and vegetables contain pigments giving them their gorgeous colours.  These pigments are sensitive to pH, minerals or metals in water, heat, light, oxygen and food additives (eg. anti-caking agents) in other ingredients. 

• garlic - Garlic can turn blue or green when used in a pickling solution (eg. dill pickles) due to the anthocyanins it contains.  These are water soluble pigments that turn blue, green or purple in an acid solution (eg. pickle brine).  The flavour remains unchanged and it is safe to eat.
• green beans - The ends of green bans can turn brown after processing due to an enzymatic reaction that changes the chlorophyll from green to brown.  This is a common occurrence with raw packed green beans and it can cause the water in the jar to look brownish as well.  To avoid this problem, use the hot pack method.  This will destroy the enzyme.
• corn - Sweet corn can darken or turn brown when home canned.  Sweet corn contains sugar that caramelizes under the heat of processing causing both a flavour and colour change.  The amount of sugar in sweet corn is determined by the variety.  In general yellow sweet corn can's better than bi-colour sweet corn with less browning.  It is very important to not over process corn.
• cucumbers - Two anomalies occur with pickles that do not affect their safety.  If table salt is used rather than pickling salt, the brine will become cloudy.  Table salt contains iodine and anti-caking agents that interact with the vinegar.  Avoid this by using pickling or kosher salt only.  Tap water contains minerals and additives (chlorine, fluoride) that can cause the brine to become cloudy.   Prevent this by using filtered water.  Cucumbers contain an enzyme in the blossom end that cause them to become soft.  When pickling, always cut a thin slice from the blossom end to remove the enzyme for crispier pickles. 
• tomatoes - The pulp and juice in home canned tomatoes may separate during storage.  This is caused by the enzyme, Pectase, that is activated when tomatoes are cut.  Separation can be reduced by heating tomatoes quickly over high heat to 180ºF (82ºC) to destroy the enzyme as soon as they are cut.  Tomatoes will darken if cooked in aluminum cookware.  Avoid this by using stainless steel or enamel coated cookware.  Hard, white calcium nitrate deposits can occur mainly in home canned ketchup.  This is a result of mashing or pureeing.  They are safe to eat but if throughout the product, the texture may be undesirable.
• cauliflower - Cauliflower will remain white in acidic solutions but sometimes pickling liquid can cause pigments in cauliflower to change to pink.  There is do preventative measure.  Pink cauliflower is still safe to eat.
• pears - Pears can turn pink due to over processing or enzymatic reactions.  They are safe to eat.  Pears should be treated with ascorbic acid or lemon juice to prevent browning due to oxidation.
• beets - The pigments in beets are pH sensitive.  They are red in acids and blue in alkalis so pickled beets should be red or a deep burgundy.  If they are blue, the solution was not acidic enough to be processed in a BWB canner and should be discarded.  They are not safe to consume.  Beets can turn white, yellow or pale red when home canned.  The anthocyanins (pigments) are sensitive to high temperatures causing the colour change.  The beets are safe to consume.