I pickled these in the normal way and to my utter surprise they have turned blue. A brief google later:

Tip - Why Garlic in Vinegar Turns Blue or Green
Sometimes garlic in vinegar turns blue/green. Changing the pH with vinegar brings about changes in the pigments in the cut garlic. Although undesirable, the changes in colour do not make the garlic unsafe to eat. It is reported that garlic which has been stored for four weeks above 23°C prior to processing does not change colour.

Tags: blog, preserves, Jams and pickles