Making your own rock candy flavorings at home is easy, but requires even more patience than making rock candy. You'll be making extract, like the familiar vanilla extract, but you can make it with virtually anything--fruits, vegetables, herbs or spices. If you're brave enough, make all of the unusual extracts you want; you just might discover that black pepper rock candy is tastier than it sounds.
Clean and dry a large jar with a rubber seal and an airtight lid.
Prepare the ingredient or ingredients you want to use to make your flavoring. If you're using something flavorful and fairly self contained like cinnamon sticks or peppercorns, you don't need to do anything. Vanilla beans should be sliced down the middle to expose their contents. If you're using a fruit or vegetable, wash and peel the fruit and chop it into small cubes. If you're using fresh herbs, chop them coarsely. Keep in mind that you will need to strain this out at the end of the process, so avoid using dried powders or anything that will completely disintegrate after soaking in liquid. For best results, use only one ingredient and make multiple flavorings if you want to combine flavors.
Put your flavoring ingredient in the bottom of the jar.
Pour in some vodka. You can approximate how much you add, but try to aim for a five-to-one vodka to ingredient volume ratio for all dried ingredients, and a three-to-one ratio for all fresh ingredients.
Seal the jar tightly. Give it a good shake and store it somewhere cool and dry.
Wait eight weeks while the mixture turns into an extract. Every three or four days or so, give the jar a shake.
Pour the mixture through a very fine mesh strainer into another clean container. You may need to strain the mixture a few times to get out all of the pulp and particles, but it's worth taking your time to strain your extract well.
Store the extract in small airtight jars or bottles. Preferably use colored glass instead of clear glass to best preserve the extract flavor.
A little of a good extract will go a long way. Follow your rock candy recipe to determine the right amount for your batch.