Lemon flower and fruits |
Lemon growing in the Indian Himalayas |
In antiquity, citron was more grown as an ornamental and medicine than for food usage; Romans preferred vinegar and occasionally sumac berries to set sour accents in their cuisine (see silphion for details). To my knowledge, not even citron peel has been used culinarily in Rome, but the Apicius suggests wine flavoured with citrus leaves as a surrogate for rose wine (see silphion).
The contemporary culinary importance of citron is due to its thick peel,
which is first cured in salt water and then candied. The product obtained,
named inaccurately candied lemon peel or succade, is often
used to flavour
cakes; in Central Europe, it is often employed for the numerous cakes and
cookies served at Christmas time. Besides the culinary types, there are
also ornamental breeds of citron grown for their large, aromatic and often
spectacularly shaped fruits. An example is the cultivar known as
cf. sarcodactylus, which is known as
Buddha’s hands
(calqued on Chinese fo shou gan [佛手柑] Buddha hand tangerine
):
In this particular cultivar, the citron
wedges
are joined only at the base of the fruit;
at the opposite end, the wedges separate and form a bizarre structure
resembling fingers sprouting from a hand (or a polytentacled cephalopod).
Lemon, on the other side, is mostly valued for its juice. Lemon juice displays
a unique, intensive acidity which is at the same time tart and fruity. There is
hardly one single cuisine in the world that does not make use of lemon juice
(or the similar, but more aromatic lime juice).
Lemon juice is especially popular in the East Mediterranean, e. g., in Lebanese
tabbouleh (see parsley), and also
in Italy. See also mango for more information on
sour spices.
Lemon tree |
Lemon plant with flowers and fruits |
Lemon juice (and sometimes also grated lemon peel) is the key ingredient in the famed Greek yolk-lemon sauce avgolemono [αυγολέμονο]. In its simplest form, this is just prepared from fish or meat broth, lemon juice, egg yolks, and a pinch of black pepper; possible elaborations include cornstarch or flour as an additional thickener, or addition of butter to make the sauce richer; in the latter case, the sauce acquires in part the character of emulgated sauces, see tarragon. Avgolemono is wonderfully creamy, light and refreshingly acidic; the sauce is usually served to boiled meats or vegetables, but it can also be made into a more hearty soup by adding rice or noodles.
In Western cuisine, fried or grilled fish is nearly always served with a few
splashes of lemon juice which mitigates the typical 'fishy' smell and makes it
more pleasant. It is also often employed to prepare refreshing salads,
especially in the Mediterranean countries. Lemon juice intensifies the flavour
of many fruits, and a few drops of lemon juice plus a dash of sugar creates
a slightly sweet–sour tang that can make many vegetables more interesting.
Outside of the tropics, lemon juice is often (ab)used as a substitute for
lime juice.
Branch with ripe lemons |
Unripe lemon fruits on tree |
Ripe Lemons |
Culinary usage of lemon peel (lemon zest) is less important. Lemon peel goes well for types of food that are prepared with lemon juice as well, for example fish soups or fish stews. Ritschert, a traditional South Austrian stew made from white beans, smoked meat and pearl barley, was always prepared with a dash of lemon peel by my grandmother (who wouldn’t use lemon peel for any other savoury food). I am surprised that there is essentially no recipe on the web nor in cookbooks that match hers. In South Italy, where lemons are plenty and always fresh, there are even pasta sauces made from whole chopped lemons, or lemon juice plus lemon peel.
In Morocco, fresh ripe lemons are incised and pickled with a large amount of salt; after some ripening, they become a unique kinde of lemon pickle (l'hamd l'markad, Standard Arabic al-hamid al-marqad [الحامض المرقد]) that can be used as flavouring, both the zest and (more rarely) the pulp. Pickled lemon peel is an indispensable spice of Moroccan cooking and frequently employed, e. g., for the meat or fish stews known as tagine or tajine [طاجن] which are slowly braised in a clay pot carrying the same name.
When lemon peel is grated, care must be taken to limit the amount of the
white albedo (mesocarp), as the essential oil and hence the aroma is located
in the outer thin yellow pericarp exclusively; in contrast, the mesocarp
is bitter. It is almost impossible to avoid the bitter mesocarp completely,
and so grated lemon peel will always display a slightly bitter quality (which
is a value in itself, see also zedoary about
bitter spices). This bitterness makes lemon peel inappropriate for delicate
dishes and sweets; in these cases, lemon essence or candied citron are far
superior, unless one grates really carefully.