A medium-size lemon will yield about six to nine teaspoons of juice. The amount of juice in a lemon depends on its size and how a cook extracts that juice.
Lemons with coarse and thick skin have less juice. Shoppers should choose lemons with smooth skins and are heavy for their size; lemon skin with streaks of green can indicate higher acidity levels. The fruit will also last indoors at room temperature for about a week before becoming soft and wrinkled.
Many recipes include lemon zest, which is the thin, colored outer portion of the citrus peel. The white pith should never be used because it will give the dish a bitter flavor. California is the largest producer of lemons in the United States, with Arizona a distant second.