Wikipedia Article - Lemon
Lemons are a type of citrus fruit and are easily recognized by the bright yellow color of their rind/skin. Lemons are prized for their sour juice, which is usually the prime use of the lemon. However, other parts of the lemon, including it's skin/rind are used in many different dishes. Similar to the lime in flavor, the lemon tends to lack the lime's characteristic tartness.
As stated earlier, lemons are a citrus fruit and thus are of the genus Citrus of which all citrus fruits are a member.
Lemons are oval in shape, with a small protrusions near the stem and bottom of the fruit.The exact origin of the lemon has remained a mystery, though it is widely presumed that lemons are wildly grown in both India and China. In South and South East Asia, it was known for its antiseptic properties and it was used as antidote for various poisons. The lemon was later introduced to Iraq and Egypt around 700 A.D.
When buying Lemons, it is imperative to check the entire fruit for both bruising and green or white mold, which can make the fruit unfit for consumption. The rind of the lemon is resilient and can sometimes conceal these traits if not wholly inspected. Scarring on a lemon is fine, and will often be a sandy color, but the inner fruit of the lemon should never be exposed when purchasing.
Lemons should be somewhat malleable, never solid which indicates under ripeness or outright immaturity. However they should not be malleable to the point of where, if squeezed lightly, it feels like the fruit with break open, as this indicates over ripeness. Lemons should have an almost bumpy texture as Lemons that too smooth indicate over ripeness.
Coloration is also key when picking lemons. Lemons that are ripe will be bright yellow, which an oval shape, with protrusions near the stem and bottom of the fruit. Lemons that tend to be green or pale yellow will tend to be under ripe. Conversely, dull yellow, black specked or circular shape will tend to indicate over ripeness.
Washing lemons, while perhaps not crucial, is suggested, as to remove any dirt, bacteria or pesticide residue that may be present on the fruit. Washing is absolutely critical if the skin/rind or zest of the lemon is being used in your recipe.
Lemons are typically used for flavoring, due to their sour juice. However, immediately halving the lemon will make extraction of the juice more difficult. It is suggested to massage the exterior of lemon in both hands before halving, as it will assist in weakening the fruits vesicles. After this is done halving the lemon width wise is suggested, as it is far more difficult to handle when halves lengthwise. After this is done, care should be taken to remove any seeds that may be present inside the fruit, as they are inedible and undesirable. From this point, the juice of the fruit is typically squeezed from each half of the fruit as needed, sometimes with a juicer.
Lemons are also sometimes sliced as a garnish. If this is the case, massaging the lemon is not suggested as stronger vesicles will make for more effective slicing. The skin/rind or zest of the lemon is also sometimes used in certain dishes. Typically it is ground using a grater and sprinkled for additional flavor.
Lemons can be stored at room temperature for approximately a week if kept out of the direct sunlight. If they are not going to be used within a week, store them in the refrigerator where they will stay fresh for 2 to 3 weeks. Leftover fresh squeezed juice can be stored in an airtight container in the refrigerator for up to 5 days. Lemon juice and zest can be stored for longer period of time by freezing them, although this will tend to dilute the flavor somewhat. Place grated zest in an airtight freezer bag or container and store in the freezer. Freeze lemon juice in ice cube trays until solid and then place in airtight freezer bags or containers and store in the freezer.
As stated earlier, lemons are most frequently used for their juice. As such they are often squeezed over the dish in question, either during cooking or immediately after serving. It is usually used to flavor various fish and chicken dishes. However, the lemon's flavor is also used in baking, as it's sour flavor will tend to somewhat lessen the sweet flavor of many baked treats, such as muffins and cakes.