Apple juice and apple cider are both 100% apple juice squeezed, or pressed, from apples and in many respects are the same when first pressed. In some jurisdictions, especially outside North America, apple cider is not pasteurized and is generally sold with an alcoholic content. Apple juice, on the other hand, undergoes more processing and is nearly always pasteurized, and thus won’t ferment or develop any alcoholic content.
There’s a substantial year-round market in the US and Canada for both apple juice and apple cider, but the cider product enjoys special popularity around the end-of-year holiday season that begins with Thanksgiving, the traditional harvest feast days. Stores will increase their stocks of apple cider during this period to meet the increased demand, and special recipes for cider-based drinks such as mulled cider are featured. Another popular variation of apple cider is a non-alcoholic carbonated beverage called sparkling cider, which is often served as a champagne substitute. There’s also a small but vibrant year-round market for apple cider vinegar.
In the US and Canada, producers are required to process apple juice and apple cider to extend their shelf life and destroy any disease-causing organisms such as E. coli. To accomplish these goals, most producers utilize pasteurization, a method of heating liquids that destroys such pathogens; it also destroys the bacteria that convert the natural sugars to alcohol. This is why the juice and cider sold in American and Canadian supermarkets doesn’t ferment. The only exception is when producers sell directly to consumers, such as an apple orchard that presses and sells jugs of cider on its premises or from roadside stands; when such cider ferments, it's called hard cider.
The first step of production in the US and Canada is the same for both apple juice and apple cider. Ripe apples are ground up and the juice pressed out, through a strainer and into a vat. This juice is brown and opaque with minute particles of apple suspended in the liquid; if it’s going to be sold as apple cider, it may not be subject to any further filtering. If it’s going to be sold as apple juice, it will undergo additional filtering and processing to remove all apple particles, pectin and starches. This clarified juice is clear and lighter in color. Most large producers blend the juices and ciders from different species of apples to achieve a uniform flavor.
Outside the US and Canada, apple juice is produced in the same manner, and is generally sold as apple juice or sweet cider. Apple cider, on the other hand, is produced to ferment and develop an alcoholic content, much like wine. Some producers allow the apples to begin rotting, so that the fermentation process begins before the apples are pressed. There’s a substantial market in Europe for hard cider, with many different varieties available.