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Quality and Composition of Cider
The traditional aroma, flavor, texture, and color of fresh unpasteurized cider are the result of (1) the type and concentration of aromatic and flavor compounds, the amount and proportion of soluble sugars and acids, and the type and concentration of pectic compounds in the fresh apples, combined with (2) the amount of insoluble carbohydrate, gum, protein, and cell fragments left in the cider and the subsequent development of oxidized flavor and tannin compounds. Some components of apple cider are shown in Table 7-1.
The total amount of sediment formed in unclarified cider would offend many consumers, yet they expect a reasonable amount of sediment. Therefore, insoluble components responsible for the sediment in freshly squeezed juice are partially removed in making cider. If all of the insoluble components are removed quickly from freshly pressed juice, it will resemble canned apple juice in aroma, color, texture, and flavor.
The amount of sugars and acids in fresh apples can vary as much as threefold. Significant variations exist among cultivars, production regions, seasons, and maturity of apples. When the same apple cultivar is grown in the Northeast and the Southeast regions of Pennsylvania, acidity is lower in those apples grown in the Southeast. Apples from orchards located at a higher elevation or in a cooler or cloudier region generally are higher in acidity, which decreases as apples ripen before or during storage. For example, 33 to 50 percent of acidity is lost by the time a hard mature apple reaches soft-ripe maturity.
The native aroma and flavor compounds in apples are numerous (more than 80), complex, and volatile. Many of these compounds are lost in making a clarified, preserved juice (canned or frozen) from freshly squeezed apples. Tannins (more than 0.05 percent) are responsible for the astringency, while pectins (0.25 to 0.75 percent) are mostly responsible for the body or viscosity of cider.
Apples contain two primary enzymes: polyphenol oxidase and peroxidase. If these enzymes are not quickly heat-inactivated in freshly extracted apple juice, they become very active and accelerate the oxidation of tannins and natural flavors. The discoloration and stronger oxidized flavors in unpasteurized
cider are partly due to these oxidized compounds. Some consumers may prefer unpasteurized cider because of these flavors.