Fluctuating temperatures can be a common problem when you’re distilling in reflux mode, but it can be relatively easy to solve in most cases. Say you’re running your moonshine still in reflux mode, and the temperature gets up to around 172°, then drops to 144°, climbs back to 170°, and then suddenly drops to 150°. There are a variety of reasons why this can be happening, and today we’re looking at a few different ways that Rick recommends how to troubleshoot them.

You’re using an inconsistent heat source.

Some distillers use an electric hotplate under their moonshine still, which is not made to run at full blast for long periods of time. Hotplates are prone to “cycling” because they have a built-in thermostatic control, which causes them to cycle on and off. It is extremely important to use a consistent heat source when running a moonshine still in reflux mode. Electric heating elements are safer than gas heat, so if you want to stay with electric, switch to a non-cycling heat source that was built to withstand staying at a high temperature for extended periods of time, like our Band Heater or Still Heater. If you want to go with gas heat, just make sure that you protect the bottom of your kettle from damage from potential heat surges.

Your cooling water is inconsistent.

Again with the consistency here. If either the temperature of your cooling water or the flow rate is fluctuating, that will affect your vapor temp at the top of your moonshine still column. Using a submersible water pump to recirculate your cooling water works great for being able to monitor the temperature of your water. Rick recommends to get it as cold as you can, so just keep adding ice to your water reservoir where you’re cycling the water from (usually a large cooler or clean and empty trash can).

Another reason why the cooling water could be the culprit is if the flow rate of the water is inconsistent, speeding up or slowing down. We’ve also seen this commonly happen with distillers who use their outdoor hose as the water pressure can change.

You’re distilling outside on a breezy day.

Outside temperature is one of the many factors that affects your run. If a strong breeze or gust of wind blows in, that affects the surrounding temperature of not only the moonshine still itself but also the cooling water as it flows through the cooling lines. You’ll want to either wait and distill on a day that isn’t so blustery, or find a way to protect your moonshine still from the wind.

You’ve packed your distillation column too tightly.

Column packing serves multiple purposes when you are distilling in reflux mode, one of them being to provide more surface area inside the distillation column for early condensation, which helps increase reflux. Therefore, you want to pack the entire reflux column to get in as much surface area as you can. However, if you pack your column with rolls of copper mesh, there’s a chance that you could have rolled the copper mesh too tightly, leaving too little void space for the vapor to rise and the liquid to fall. This creates a barrier, causing blockages and surges, which affects the temperature at the top of the moonshine still when the vapor is finally able to rush through. This cycle repeats itself, leading to yo-yoing temperatures throughout the blocking and surging process. Try taking out your copper mesh and checking for any obstructions caused by tight copper mesh.

I hope this info helps you as you’re learning more about distilling! If you have any additional questions, feel free to contact us here.