Infusing liquor with a new set of flavors is something you can do in fairly low tech way. All you need is a sterile glass container with a lid, the spirit of your choice, and the infusion ingredient(s). Add the ingredient to the booze, and let the mixture sit in a cool, dark place for a week or two. Easy right? Here are some tips to get you started.
Choose Your Spirit
Vodka, rum, tequila, and brandy are easiest to infuse. Whiskey and gin start out with more flavors and aromatics, so it's a little more challenging to add flavor of your own that marries well with the existing herbal or smoky notes. An exception to the no whiskey/gin rule is bourbon which takes very naturally to a wide variety of flavors — strawberry, cherry, pear, peanuts and of course bacon. And while infusing gin with citrus or herbs can be tricky, it does take well to tomatoes, cucumbers, or teas.
You want a nice spirit for this, but it doesn't have to be too nice. Higher end hooch won't carry the flavors any better than medium shelf so save those for drinking straight. But stay away from the cheapest choices. Rotgut will always be rotgut, no matter how many herbs and spices you add.
Choose Your Primary Flavor
This is where you you want to invest in quality ingredients. The better the flavors you put in, the better your final infusion will be. Use the lushest, ripest fruit or vegetable you can find, the freshest herbs. If you want citrus flavors, it is better to use the rinds than the pulps, for a purer flavor.
Choose Your Secondary Flavors
The secondary flavor will make your mix more complex by either complimenting and heightening the original flavor, or by smoothing it out.
Mix It Up
Place your ingredients in the jar and cover fully with your spirit. Seal it tightly.
Taste Regularly
Taste your infusion daily. That's right daily. Some ingredients and flavors can take as long as ten days to fully bloom and develop while others can be done in just a few days. Be especially wary of ingredients like peppers and cloves which can become overwhelming very quickly. If the brew is weaker than you would like after a few days, feel free to add more of your ingredients. When your infusion tastes the way you like it it's done. Remember to make sure that your containers are tightly sealed between tastings.
Strain
Yes, the ingredients look really pretty in the jar or bottle. But remember that as long as the ingredient is in there, it is leaching flavor into the liquid, which can become overwhelming. Also now you have all of those bourbon-soaked cherries, or rum infused pineapple slices for snacking, garnish, or ingredients in another dish.