Cherries are classified botanically as a drupe, a type of stone fruit characterized by a fleshy outer part surrounding a single hard pit. These fruits develop from the flowers of trees belonging to the genus Prunus, specifically Prunus avium (sweet cherries) and Prunus cerasus (sour or tart cherries). The cherry’s journey involves a complex biological cycle followed by distinct agricultural and industrial processes. These processes are tailored for the fresh market or for preserved products, such as the bright red Maraschino cherry.
The Natural Growth Cycle of Cherries
Cherry trees begin their year dormant, requiring specific chill hours to transition into the spring blooming phase. Once dormancy requirements are met, the trees produce delicate flowers, which must be successfully pollinated to begin forming fruit. Sweet cherry varieties (Prunus avium) are largely self-incompatible, meaning they require pollen from a genetically different, compatible cultivar to set fruit.
This need for cross-pollination means growers must plant specific “pollenizer” varieties nearby to ensure a successful harvest. Sour cherries (Prunus cerasus) are mostly self-fertile, allowing a single tree to produce fruit without a partner tree. Both types rely heavily on insect pollinators, such as honeybees and bumblebees, since wind alone is not effective for transferring the heavy pollen.
Following successful fertilization, the ovary wall develops around the single seed, forming the fleshy pericarp, which is the edible part. The fruit then enters a rapid growth phase, swelling in size before the final ripening stage. During this stage, the fruit accumulates sugars and develops its characteristic red color from anthocyanin pigments. Sour cherries generally have a shorter development period than sweet cherries and are typically harvested earlier.
Harvesting and Initial Sorting
Determining the precise time to harvest is important because cherries do not continue to ripen or increase their sugar content once removed from the tree. Harvesting methods vary based on the intended market. Sweet cherries destined for the fresh market are predominantly hand-picked. Workers carefully detach the fruit while keeping the stem intact to minimize bruising and prolong shelf life.
Cherries intended for processing, such as those used for juice, pie filling, or Maraschino cherries, are often harvested using mechanical shakers. These machines clamp onto the trunk and vibrate vigorously, causing the fruit to fall onto catching frames or tarps below. After collection, the fruit is quickly transported to a packing facility for initial sorting and washing to remove debris.
A procedure called hydro-cooling is then performed, where the cherries are submerged with icy cold water. This process rapidly removes field heat, which is necessary to maintain firmness and slow deterioration. High-tech optical sorters analyze the fruit to grade it by size and quality, diverting any cherries with defects away from the premium fresh-market stream.
Manufacturing the Maraschino Cherry
The industrial transformation of a raw cherry into a preserved Maraschino cherry begins by stripping the fruit of its original characteristics. Lighter-colored varieties, such as Royal Ann or Gold cherries, are typically used. They are first immersed in a chemical brining solution, often containing sulfur dioxide or calcium chloride. This brine serves the dual purpose of firming the fruit’s texture and bleaching away its natural color.
Calcium is included in the brine to react with the cherry’s pectin, forming salt linkages that stabilize the cell walls and prevent the fruit from becoming mushy during later processing. This brining phase can last several weeks, resulting in a firm, pale, straw-yellow cherry with a neutral flavor profile. The bleached cherries are then thoroughly washed, or leached, with water over several days to remove the chemical preservatives.
The cherries then undergo a slow, controlled soaking in a sweetening syrup. This sugaring process is gradual, moving the cherries through increasingly concentrated sugar solutions to prevent osmotic shock, which would otherwise cause the fruit to shrivel. Once the sugar concentration reaches the desired level, the cherries are infused with artificial color and flavor.
The characteristic bright, uniform red hue is achieved by adding FD&C Red Dye \#40 to the syrup. The distinct flavor is added next, often using benzaldehyde, an aromatic compound that imparts a strong, almond-like taste. Finally, the finished Maraschino cherries are packed into jars with the colored, flavored syrup and sealed for preservation.