of years. One is to cook them in alkaline
water, which has very few hydrogen ions that
are free to displace the magnesium in
chlorophyll. The great 19th-century French
chef Antonin Carême de-acidified his cooking
water with wood ash; today baking soda
(sodium bicarbonate) is the easiest. The other
chemical trick is to add to the cooking water
other metals — copper and zinc — that can
replace magnesium in the chlorophyll
molecule, and resist displacement by
hydrogen. However, both tricks have
disadvantages. Copper and zinc are essential
trace nutrients, but in doses of more than a
few milligrams they can be toxic. And while
there’s nothing toxic about sodium
bicarbonate, excessively alkaline conditions
can turn vegetable texture to mush (p. 282),
speed the destruction of vitamins, and leave a
soapy off-taste.
Watch the Water, Time, and Sauce Dulling of