Pot still design and Reflux
More reflux means milder and clearer whisky. Pot still has several desing type to adjust reflux.
Heating Source
Direct heating has much faster heating than indirect steam heating. Faster heating mean less reflux so direct heating type has less reflux and makes more powerful whisky.
Direct coal
It is original heating type pot still.
For wash till, it needs rummager chain for anti burn stick pot still inside. Normally direct heating type makes more powerful whisky than indirect steam heating pot still.
Ex. Only Yoichi.
Direct gas
There are 4 distilleries for using gas direct heating pot still in the world today.
For wash till, it needs rummager chain for anti burn stick pot still inside. Normally direct heating type makes more powerful whisky than indirect steam heating pot still.
Ex. Only Glenfiddich, Glenfarclas, Macallan and Springbank.
Steam coil
It is indirect heating type. High temperature steam is going through coil and then coil heats and distills wash or low wine.
It is much less burn stick pot still inside.
Steam cylinder
It is also indirect heating type. High temperature steam is going through cylinder and then cylinder heats and distills wash or low wine.
it is much more easider to remove burn stick.
Pot body
More surface area makes more reflux. Lanterna type and Bulge type were developed for increasing reflux.
Onion/Pear
It is most less refulux type pot still.
Lantern
It is middle refulux type pot still.
Bulge/Boil Ball
It is most refulux type pot still.
Pot neck
Tere are also some custom type of pot still neck to increase cooling to increase reflux.
Long neck
Long neck means that steam wash needs to travel more distance before condensor. So it means morereflux.
Ex. Glenmorangie
Water Jacket Head
Some distillery puts water cooling jacket on pot still neck for increasing reflux.
Ex. Glen Grant, Dalmore
Lomond
Some distillery insert copper plate in pot still neck for increasing reflux.
Ex. Glenburgie, Scapa, Loch Lomond
Lyne Arm
Upward arm and Purifier make more condense in lyne arm and send back condensed liquid to pot still.
Downward works oppositely.
Upward
More upward angle arm causes more reflux and if further reflux is needed, longer and/or thicker arm make more reflux.
Downward
More downward angle arm causes less reflux. It means that it increases carrying over more heavy contents to whisky and it become oily and powerful one.
Purifier
Rectifiler increases colling and returns condensed liquid to pot still via bypass.
Ex. Ardbeg, Glenlossie and Talisker.
Condensing system
Condenser reconverts wash steam to liquid.
Warm condenser
It is traditional condenser. Copper warm tube remove sulfur compounds from wash steam during cendensing.
Fin & Tube condenser
It is improved condenser which has more copper surface area. It means more capability to remove sulfur compounds.