Whisky from the past (Part 3)
22.05.20 by Tim Foster – Sales Manager, Lindores Abbey Distillery
So far we’ve found that barley variety, malting and fermentation were a bit different in the 19th century. But what of distillation? Hmm…
The obvious thing to focus on is the ‘wormtub’ condenser and rightly so. These days most Scottish distilleries use shell and tube condensers which are really efficient at turning vapour into lovely potable spirit. Their construction also means that spirit vapours come into contact with more copper and hence we get a more refined spirit (in theory… but not always).
The wormtub condenser is usually situated outside the still house and sits in a big bucket of water. Condensing spirit is really easy in winter, as Scotland tends to have an abundance of cold water during the winter months. Not as easy in summer though, this is where the water source and/or means of cooling it is important.
A full and fast flowing water supply will give a lot of cold water. But where that isn’t always an option, cooling towers are becoming pretty commonplace, allowing the regulation of water temperature.
In the past there is a good chance that the spirit produced could get pretty sulphury and by today’s standards would have been considered heavy (to say the least).
At the coal face
Next up, direct fired stills. Like using shell and tube condensers, we also heat our stills differently these days. Indirect fired stills use steam running through coils (they look like radiators, which is what they are), they’re efficient and more to the point, way easier to control.
Back in the day, heating the stills was done by lighting a big fire underneath them. Consider this, pure ethanol has a flash point of 20 degrees celsius – meaning any vapour coming into contact with a an ignition source will combust. It’s one of the reasons you’re not permitted to use flash photography when you visit modern distilleries. So, flames are not a great idea in a distillery. Common sense really.
What are the impacts on the spirit? We’ll look at temperature control first.
You’re familiar with distillation right? As wash/low wines are heated, the liquid starts to boil and vapours are released. Ethanol has a lower boiling point than water, so it ‘distils’ first. As the vapours rise up the still they come into contact with the copper inside the stills and the condenser and each interaction causes a chemical reaction that removes impurities from the spirit.
We can manipulate this by controlling something called reflux, basically we raise and lower the heat.. just like in cooking. A gentler boil will give more reflux. Broadly speaking more reflux = lighter spirit. There is another thing called ‘entrainment’, which happens when the bubbling liquid boils over (this is bad). Not having effective control over the heating in the 19th century would almost certainly have caused issues and inconsistency. More evidence of heavy/sulphury spirit.
The other massive difference was a phenomenon called ‘fouling’, which sounds horrid. In a direct fired still, you get things called hotspots. These are areas where heat builds up. When this happens solids from the fermentation start to burn to the surface, not good. It’s the malliard thing again (see ‘Cask Life’ post). These burnt bits can give a bitter and astringent taste (burnt toast anyone?).
Fortunately, there is a solution to this! A rummager. ‘A whatager?’ A rummager. A mechanical thingy bob that rotates round the inside of the still, dragging chains as it does. The aim of rummaging is to scrub off ‘fouling’ before it burns onto the surface of the still. There are a handful of distilleries that still direct fire, such as Glenfiddich, Glenfarclas and Springbank.
There is only one open fired distillery in the world, Yoichi in Japan (having visited Japan and seeing their obsession with Health and Safety this utterly baffles me, but is uber cool). The whisky produced at direct fired distilleries is widely described as being ‘heavier’. You get the picture. Old distilling = heavier spirit.
I had promised to cover maturation in this journal post. But I’m going to leave you on tenterhooks and cover it next week. Sorry to be a tease.
Stay safe and see you next week. Tim
Cask Ownership at Lindores Abbey Distillery
The distillery is of course currently closed but you can still chat to Elliot, our Cask Custodian about our cask ownership scheme and what is involved. We still have a lot of exciting projects going on with different types of casks coming through – but they are all very limited so get in touch if you would like to explore different opportunities within the whisky world. You can contact Elliot on firstname.lastname@example.org or find out more at https://lindoresabbeydistillery.com/welcome-lindores-abbey-distillery/cask-ownership/