Apple wine is different from hard cider in that it is usually around 10-12% alcohol and is fermented with the addition of sugar and other ingredients such as acid blend and wine tannin for flavor balance. Hard cider typically runs around 5% alcohol and is produced by simply allowing the apple juice to ferment on the sugars that are naturally present.
The features that make Applejack different from hard cider or apple wine is that it has a higher concentration of alcohol. It can be as high as 30% alcohol or 60 proof. Also, the apple flavor is more intense or concentrated.
Applejack is made by storing completely finished apple wine at below freezing temperatures. What happens is the water that is in the apple wine freezes and rises to the top while the alcohol stays in liquid form - a process known as fractional crystallization. Each day you simply scoop off the ice that has formed, causing the alcohol and the apple flavor that is left behind to become more concentrated.
Each day you will notice that the amount of ice that is forming will be less and less, until eventually no more ice will form at all at that particular temperature. The following will give you an idea of how concentrated the alcohol can become at a given temperature: at zero degrees ice will form until the liquid reaches 14% alcohol by volume. At 10 below ice will form until it reaches 20%. At 20 below 27% can be made. And, at 30 below 33% alcohol can be obtained.
Applejack was very popular among the New England colonies. Barrels of apple wine would be set out in sheds during January and February when the temperatures where blistering cold. And, by first thaw it would be ready to drink.
If it does not get all that cold in your area, the same effect can be duplicated by using a deep freezer. Do not use glass containers as they as they will more than likely crack. A soft plastic, food-grade pail with lid seems to work well for this purpose. Just put your apple wine in the deep freezer, set the thermostat as low as it will go. Then every day scoop off the ice, until there is no more ice to scoop.
The alcohol level the wine starts out at is not all that important. Whether it is 8% or 12% the same concentration level will eventually be reached regardless. The only thing that changes is the amount of ice you will need to remove to get to that point.
Another thing to note here is that while traditionally this method is applied to apple wines, it can also be applied to other wines just the same. Other good candidates would be: Pear, Mead, Watermelon, Peach, Strawberry - primarily fruits that do not have a strong, assertive flavor to begin with. Have fun and experiment with a gallon or two.
You can find all of the necessary ingredients for making your wine at Adventures in Homebrewing.