Classic method called Maceration which was a very popular couple of years ago where every bartender was proudly exposing infusion jars on the back bar.
This method requires a minimum effort as simple as steeping a fruit, herb or spice in alcohol and then let it sit for a couple of hours or days depending on the ingredient, shake it regularly.
Despite all the modern practices used today it still remains a very effective way of infusing a spirit as you keep the ingredient sealed in the jar where it preserves the flavour.
The science behind the infusion?
There are two processes which occur when you’re infusing certain ingredient in alcohol Osmosis and Dissolution.
Osmosis happens when nature strives for balance. Basically, fresh ingredients such as fruits and vegetables contain a lot of water and alcohol a lot less so water from fruit flows naturally(with other compounds) to an ingredient which has less water to even things out and reach the equilibrium.
The second process Dissolution happens with dried flavourings in which there is no water to be exchanged so the process is about releasing and dissolving compounds into the alcohol. For alcohol to be more effective it needs to be in high concentration at least 40%ABV.
What Influences the infusion?
In its simplest form infusion of a liquid is affected by the size, weight, pressure and temperature of the ingredient to be infused and alcohol content.
It’s generally accepted that chopping or grinding the ingredients to smaller sizes will make it infuse four times faster. It has not the only effect on the time it takes to infuse it but also on the amount of ingredient required.
What ingredients to infuse?
Think of it as a chef and start experimenting and pairing different flavours, possibilities are endless. Time of the infusion depends on particular ingredient so don’t forget to sample the infusion regularly and the small pieces double strain it through the coffee filter or cheesecloth.