R – as in Reflux

What is a Reflux Condenser?

The reflux condenser at St. Kilian is an additional cooling coil located inside the Lyne Arm of the 6,000-liter spirit pot still, the fine spirit still. It is a spindled copper tube through which cooling water flows.

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Is Reflux Condenser an official term?

The term reflux condenser is most likely not an official name. This important component was named this by St. Kilian Distillers. A reflux condenser could best be described as an enhancer or dephlegmator.

Who had the idea for the reflux condenser?

The idea of installing a reflux condenser in the Lyne Arm of the Spirit Still at St. Kilian came from Irish Master Distiller David F. Hynes. David is our mentor and provided St. Kilian Team with advice and support, especially during the planning and construction phase of the distillery.

What does a reflux condenser do?

Since cooling water flows through the spindled copper tube in a controlled manner, the temperature in the Lyne Arm can be regulated, and thus the reflux can be controlled.

What does reflux mean?

When liquid evaporates during distillation inside the still, and the rising vapors are cooled again before reaching the condenser due to the cooler ambient temperature of the pot still, condensing and flowing back into the still, this is called reflux.

What does reflux do?

With a lot of reflux, i.e., a high reflux rate, the vapors or the returning liquid have multiple contacts with copper. A lot of copper contact reduces the proportion of unpleasant sulfur compounds in the distillate, as copper has a high affinity for sulfur and can chemically bind it. Thus, with a high reflux rate, ultimately only the lightest vapors reach the condenser, are liquefied in it, and collected. This results in a light distillate. Light in the sense of volatile substances and aromas that are obtained from the wash or, in the second distillation in the spirit still, from the low wines. The light distillate, the New Make Spirit, tastes comparatively mild and fruity. On the other hand, the less copper contact and reflux there is, the edgier, harsher, and more characterful the New Make Spirit becomes.

What effect does the reflux condenser have?

Cold water with a specific temperature and a controlled flow rate can be passed through the reflux condenser. This allows the reflux to be precisely controlled, and if desired, further enhanced up to maximization, thus obtaining a multiply distilled spirit. This multiple distillation is called "multiple distilled" in English. As a result, only the lightest and lowest-boiling substances reach the condenser and are liquefied there.

What significance does the reflux condenser have for St. Kilian?

The reflux condenser is an essential element for us to influence the spirit character during distillation. And this influence of the reflux condenser is enormous, because from one and the same raw material, the wash, very different New Make Spirits can be produced on a single distillation plant. This supports St. Kilian Distillers' experimental spirit and is exciting at the same time.

Has the reflux condenser already been used in practice?

A strong reflux also affects the smokiness, mouthfeel, and sweetness of the New Make Spirit, as it was used for the Signature Edition Eleven. Because even though peated malt from the Scottish Highlands with 54 ppm was used, this limited single malt whisky is only mildly smoky. Due to the maximum reflux, only a few smoke aromas reach the condenser, the remaining smoke is better integrated, and the spirit becomes smoother, sweeter, and has a great mouthfeel. In this way, a wonderfully round single malt is obtained after just three years, as the Signature Edition Eleven proves.