How to make Kahlua coffee liqueur at home

This is a simple recipe with only a few ingredients. There are many recipes for the liqueur on the Internet, some of which make some very strong booze. I tried to get as close to original Kahlúa as I could, with the same alcohol content and texture.

Makes about 2½ cups (600ml).
By Dennis W. Viau; modified from several recipes.

Multiply the following proportions to make larger amounts. Some people make this by the gallon to give bottles away as gifts.

Ingredients:

½ cup (120ml) water
¾ cup (150g) granulated sugar (can be increased to 1 cup (200g))
1 tablespoon instant coffee
½ cup (120ml) light corn syrup
1 teaspoon vanilla extract
1 cup rum

Directions:

Combine the water and sugar in a saucepan and heat to dissolve the sugar, stirring often, heating to near a boil. Remove from the heat and add the coffee; stir to dissolve. Add the corn syrup and vanilla, stirring to blend. Add the rum and blend thoroughly. Allow the mixture to cool, then bottle.