So I’ve just come back from a holiday in Scotland, splitting my time between Speyside and Islay, which means I’m full of things to write about. Lots of interesting people and places, but also a lot of whiskies and distilleries. Now, I’m quite into my ales as well, and when you visit a brewery, you feel like not only has the brewery grown organically from its humble beginnings, but the equipment has too. With a distillery, on the other hand, while the company itself will have its own quirks and stories, the equipment and processes are more alike than they are different. There will be little things here and there (the marketing guys will tell you they’re key differentiators that give them a superior spirit), but the stills are always copper and pot-shaped, and the malt mill is always made by Porteus. So I thought that my first article should be a general run-down of a working malt distillery, and then I’d get on to the specifics later.
To make whisky, you basically need to distil beer, and to make a beer, you need yeast to convert sugar into alcohol. Barley comes with its own handy store of sugar, but the problem is, that store is locked. The way to unlock it is a process called malting. You give the barley grains water and warmth, and make them think it’s time to start growing. After they’ve taken the bait and started to convert their energy store of starch into sugars, ready to put out roots and shoots, you dry them out again, crushing their fragile hopes and dreams and co-opting their hard-earned bounty for your own nefarious purposes. Once the malting is done, you then crush them more literally, cracking their shells and grinding their tender innards, before drowning them in water and allowing yeast to feed on their lifeblood. So that’s nice.
Most distilleries get their barley pre-prepared, so to speak. The Port Ellen maltings are always running, producing malt for Diageo, and independents like Bairds and Crisp produce hundreds of thousands of tonnes a year. Distilleries like BenRiach and Laphroaig have their own malting floors, but these aren’t enough to produce all the malt they need, and they buy in the rest. I had heard Springbank use only their own maltings, but they seem to skirt the subject on their website, so possibly this is no longer the case.
Once the malt has arrived at the distillery, it gets milled (in a mill) and mashed (in a mash tun). I mentioned the name Porteus earlier, and this is where they come in. Porteus used to make malt mills of incredible quality and longevity – the one we saw in Aberlour was about 55 years old, and reckoned to be a third of the way through its working life. Almost every distillery bought one, and then never needed to buy another. In fact, they very rarely needed to even get repaired, and so Porteus went broke. That’s business, folks.
The milled barley is then passed on to the mash tun and soaked in warm water to draw out the sugars. The standard approach seems to be three lots of water at around 65°C, 75°C and 85°C, although some distilleries use a 4th. The first two rinses are the wort. These draw out most of the sugars and are fed into an underback, which is basically a holding vat where the wort is cooled. The third rinse is generally too low in sugar to be fermented, and after being drawn off is added to the first lot of water for the next mash. The leftover grain in the mash tun is called draff, and is usually sold to farmers to feed their livestock. With me so far? It gets easier from here, I promise.
The wort is fed into washbacks, giant vats made either of Oregon pine or stainless steel. Yeast is added and the wort allowed to ferment for around 3 days, creating a beer at about 8% ABV, known as the wash. There’s honestly not a huge amount of difference between pine and steel washbacks – proponents of the former will tell you it’s more traditional, and that there is a strain of bacteria in the wood performing lactic fermentation, adding flavour to the wash. Proponents of the latter will say there’s practically no difference, and steel is easier to keep clean, or that they prefer a slightly softer, cleaner wash. Apples and pears, innit?
The fermented wash is sent to the wash still and distilled to around 30% ABV. This liquid is known as the low wines, and the process is pretty straightforward. It starts to get a bit more complicated when these are sent to the spirit still to be distilled a second time. The first stuff to come off in the second distillation is pretty strong stuff, very high in alcohol content and containing unwanted types of alcohol like methanol, which makes you go blind. This is known are the head, or foreshots. After 10-20 minutes, the alcohol content has dropped to around 75%, and the stillman can start to collect the heart, or middle cut, which is what will be casked and matured. This is collected until the alcohol content has dropped to about 63% (after about 3 hours), when the stillman will divert the flow of spirit again and collect the tails, or feints, at a lower alcohol content. There’s no need for subtlety now, so the heat will usually be whacked up to 11, and the remaining alcohol distilled off as fast as possible.
The foreshots and feints are collected and added to the next batch of low wines to be redistilled. The residue in the wash still is a yeasty syrup known as pot ale which is again often sold as animal feed. The residue in the spirit still is called spent lees. It’s more or less just water, with some copper from the still. This is harmless and is often just discharged into the sea.
And then the good part starts. The new spirit is often reduced to around 63.5% in strength and filled to casks to mature. Talented men and women with a better nose than I will ever have do their bit, and a few years later we get a drop of dreams served up. Slàinte mhath!