Start by selecting the ripest plums you can find, as the sugar content is crucial for natural fermentation. Wash the plums thoroughly in cold water to remove any debris or impurities. I learned early on that any unwelcome particles can spoil the mash, leading to off-flavors in the final product.

Halve the plums and remove the pits. The pits can impart a bitter taste if left in during fermentation, a mistake I made in my first batch that resulted in a less than desirable rakija. Place the halved plums into a large fermentation vessel, such as a wooden barrel or food-grade plastic container.

Dissolve the yeast in a small amount of lukewarm water and add it to the plums. While not traditional, as wild yeasts typically initiate fermentation, I've found that using a controlled yeast strain can lead to a more consistent end product.

Mash the plums gently with a clean mashing tool or your hands. This releases the juices and starts the fermentation process. Be careful not to over-mash, as this can break down the fruit too much and create a dense, difficult-to-ferment slurry.

Cover the vessel with a breathable cloth to keep out insects and debris while allowing natural yeasts to enter. Store it in a cool, dark place. The fermentation process can take anywhere from 4 to 8 weeks, depending on the temperature and sugar content. Stir the mash every few days to prevent mold from forming on the surface and to ensure even fermentation. I've learned that patience during this stage is key; rushing it can result in an incomplete fermentation and a lower-quality rakija.

Once fermentation is complete, indicated by the cessation of bubbling and a clear separation of solids and liquid, it's time to distill. Transfer the liquid to a copper still, leaving behind the solids. The distillation process should be done slowly and carefully to separate the alcohol from any unwanted compounds. I remember my first distillation being too rapid, which caused a mix of high and low boiling point compounds, resulting in a harsh taste.

Collect the first 5% of the distillate and set it aside. This is the 'heads,' containing methanol and other volatile compounds, and should not be consumed. Continue distilling until you reach the 'tails,' which emerge towards the end and can be identified by a drop in temperature and a change in aroma. The 'hearts' in between are what you're after; this is the purest and most flavorful part of the distillate.

Dilute the 'hearts' with water to your desired alcohol content, typically around 40-45% ABV for rakija. Be precise with your measurements; too much water can dilute the flavor, while too little can make the rakija too strong. I use an alcoholmeter to ensure accuracy.

Age the rakija in oak barrels or glass bottles. Aging allows the flavors to mellow and meld, resulting in a smoother, more rounded spirit. I've found that a minimum of six months aging makes a significant difference, though many connoisseurs prefer several years.