The first 5% of your run will consist of the foreshots. Foreshots contain methanol which is an extremely volatile and toxic alcohol. As a standard practice a good rule of thumb is to throw out the first 250 ml per 5 gallons as this part of your run will consist of these foreshots.
Do not consume this part of your run!
Be sure to isolate the foreshots thoroughly and throw them out. Consuming methanol can cause an array of issues including blindness.
The next 30% percent of your rum run is known as the heads. Similar to the foreshots, the heads of your run are filled with volatile alcohols. One of the staples of the heads is a particularly volatile alcohol known as acetone.
Acetone has a distinct, solvent-like smell, making its identification pretty easy to recognize. Drinking your heads won’t make you blind but they will leave you with the worst hangover of your life.
Like your foreshots, you’ll want to isolate these and throw them out.
*Note a great way of isolating both the foreshots and heads in your run is to bring your still to around 168 °F and keep it there for around 10 minutes. The alcohol produced during this duration will consist of only foreshots and heads. Once the condenser stops producing at 168 °F, you’ll know that you’ve collected all of the foreshots and heads of the run.
If you’re following along with this guide, you have now officially gone from Googling “How to Make Rum” to actually making rum. The next 30% of your run will be the sweet spot of your rum run, the hearts. You’ll want to raise the temperature of your still to 175 °F to 180 °F range to start collecting this portion of your distillate.
You’ll notice the solvent smell of acetone taper off and a sweet-smelling ethanol come forward in your run. This is where a skillful distiller really shines. Maximizing high-quality hearts is a game of senses. You can recognize the hearts by their sweet and neutral flavor. *only taste a bit of the distillate on your finger. It’s not time for shot glasses yet my friend.
By accurately identifying where the acetone stops and the ethanol begins, a distiller maximizes their number of high quality jars of product. The main giveaways are the solvent smell of acetone and the sweet/smooth taste of ethanol.
The last 35% of your rum run will be the tails. You can recognize the tails by sight, smell and taste. You’ll see an oily film start to collect on the top of the distillate and be able to smell/taste a burnt type of flavor. The tails contain protein and carbohydrates from the wash that you don’t want in your final product.
Hold on to your tails and you can actually run them as their own wash in the future to pull out a bit more product.