long time, the combination of heat and acidity
causes the subunits to break off one by one;
and then oxygen from the air reacts with the
subunits to form true anthocyanins: so the
tannic, pale fruits become more gentle-tasting
and anything from pale pink to deep red.
(Interestingly, the similar development of
pinkness in canned pears is considered
discoloration. It’s accentuated by tin in
unenameled cans.)
Turning Red Wine into White
The sensitivity of anthocyanin pigments to
pH is the basis for a remarkable recipe in
the late Roman collection attributed to
Apicius:To make white wine out of red wine. Put
bean-meal or three egg whites into the
flask and stir for a very long time. The next
day the wine will be white. The ashes of
white grape vines have the same effect.