Most of my time today was spent learning the intricacies of distillation. We actually skipped around to different parts of the whisky making process through the week more than I’ve indicated in the last few posts, so I had already learned about mashing and fermentation on previous days and just brushed up on a few details regarding those subjects today. For the sake of keeping the blog from getting too confusing, I’ve held off writing about those two processes and will now cover them along with distilling. I don’t want this to be too technical, so I’m going to try to simplify the procedures a bit and then, at the end, go into depth with details of the process that are unique to Springbank.
On the Day 9 post, I ended with grist – the product of malted barley having been crushed in the mill. The next step is mashing, where the grist is mixed with hot water and allowed to steep for some time before the liquid is drained off. This happens in several stages at increasing temperature ranges. The purpose of this step is twofold – to activate enzymes present in the grist which will convert soluble starches into fermentable sugars, and to dissolve those sugars into the water that will be drained off the mash. The spent grains which are left (known as draff) can be used as cattle feed.
The sugar-rich water, known as wort (essentially unfermented beer), is now ready to move on to the washback. But on the way there it must go through a cooler to bring it down to a temperature that is optimal for the yeast to work in. The cooled liquid moves into the washback, a large fermentation tank, where the yeast is added. Once fermentation starts, and up until distillation begins, the liquid is known as wash.
Most single malts are double distilled. Once fermentation is complete, the wash is transferred from the washback to the Wash Still. The still is heated (by steam in most cases), and the liquid begins to boil. The alcohol boils at a lower temperature then water, so that comes off as vapor first. After reaching the top of the still, the vapors move into the lyne arm (a horizontal or near horizontal tube connected to the top of the still), and from there go through either a condenser or a worm tub, where the vapors are cooled and return to a liquid state. All of the liquid coming off the stills runs through a spirit safe, where the temperature and gravity can be checked to calculate the alcohol content. All of the liquid from the first still (called low wines) is collected in a tank called the Low Wines Receiver, until the alcohol level of the liquid coming out of the still drops to a certain point (the concentration of alcohol in the low wines will gradually decrease through the run), usually in the low single digits abv. At this point, the heat is turned off, and the liquid remaining in the still (known as pot ale) is drained off as waste, or sent out for agricultural use.
The low wines collected from the Wash Still will be mixed with the feints from the previous run on the second still (more on that in a moment), and that liquid will be transferred into the second still (which can be called the Spirit Still or the Low Wines Still, the names are interchangeable), where it is heated and a second distillation begins. This time there is a cut, the first liquid to come off the still (the heads) and the liquid that comes off at the end (the tails) are collected separately from the liquid in between, called the middle. The middle cut is the spirit that will end up in casks, eventually becoming whisky. The heads and the tails (together known as the feints) will be collected and added to the low wines on the next run, to be redistilled. When the Low Wines Still is running, the alcohol level of the liquid coming out is monitored in the spirit safe to determine when to make the cuts that separate the heads and tails from the middle. It will also be monitored to determine when to turn the heat off at the end and stop collecting the tails. The liquid remaining in the Low Wines Still at the end of the process in called spent lees, and is also drained off as waste.
The single malt Scotch whisky industry has changed a lot over the last forty to sixty years. Most distilleries are now owned by large corporations who own anywhere from a few to a few dozen distilleries. Modernization is the norm and efficiency is the name of the game. But Springbank is different, they are one of the few remaining independently owned distilleries (well, their parent company also owns an independent bottler and opened a second distillery in 2004, but you get the idea). They do every step of the process in-house and on-site. They do things the old way, the slow way. The process here is hands-on and labor intensive, but the final product is truly hand crafted, and many a devotee will tell you that the difference can be tasted.
We’ll start with the mash tun, the newest ones are all stainless steel, cold and impersonal. The not-quite-as-new ones are stainless with a copper top. The ancient relic at Springbank is cast iron with an open top. It’s a thing of beauty, with character and soul that you don’t find in contemporary industrial equipment. And here we find an interesting change in the process. Modern barley strains have improved yields dramatically (both in terms of the amount that can be grown per acre, and the amount of starch/sugar that is available per ton of grain. While using modern grains, the powers that be at Springbank have chosen to emulate the effect of using older strains. This is done putting much more water through the mash, creating a diluted wort, which will have a significantly lower original gravity than that of most other operations. Presumably, this slows down the process as well.
The washbacks at Springbank are made of Boatskin Larch. Most washbacks that you see are still wooden, made from the traditional Larch or Oregon Pine (Douglas Fir), but some distilleries are moving to longer lasting, lower maintenance stainless steel washbacks. Those who have gone to stainless will tell you it makes no difference in the flavor of the final product. The distilleries with wooden washbacks are adamant that there are bacteria in the wood that play an important part in developing the flavors of the whisky. And here too the process is slowed down. Most operations ferment for two days, three at the most. At Springbank, the fermentation goes for a minimum of 72 hours, and over 100 hours is preferred for proper flavor development. But because of the diluted wort, the wash ends up between 4.5 and 5.0% abv, in spite of the extended fermentation time. Most other distillers have a wash that is between 8% and 10% abv.
On to the stills, the traditional way to heat them would have been a coal fire directly underneath. Almost everyone has moved to steam heating coils inside the stills (indirect heat). On their Wash Still, Springbank uses a combination of direct heat from an oil fired flame, and indirect heat from a steam coil. The direct heat adds more flavor (I’m guessing it is also less efficient), but the still must have a rumager incorporated into it. The rumager is a series of copper chains that rotate around inside the still, dragging across the bottom and preventing any caramelization / burning.
The speed of distillation is another aspect that differentiates Springbank – they claim to be the slowest in the industry. Other distillers that are trying to maximize the capacity of the stills will run them faster (at a higher temperature). Slower distillation may not be as cost effective, but it is believed to produce spirit with more flavor. The people operating the stills will set the steam valve to a predetermined starting point. From here the flow rate is checked by measuring the level of the liquid in the receiver tank (the old fashioned way, with a brass dip-stick) every 30 minutes or so, and calculating how fast it is running. The steam valve is then adjusted to maintain the desired speed of distillation.
As I said above, the concentration of alcohol in the low wines coming off the Wash Still will gradually decrease over time. It starts off fairly high, and the abv of the low wines collected will average 20-25%. But at some point, the alcohol content of the liquid coming off the still gets low enough that the heat is turned off, and the process stopped. Most distillers do this around 5% abv, Springbank doesn’t stop until 1% abv. This isn’t really cost effective, as the fuel you burn to get the last few percent is worth more than the alcohol you recover at that point. I don’t know if this difference can be tasted in the final product, but it is one more example of Springbank doing things the old way and adhering to tradition.
The final distinctive feature of the Springbank still house is one that really sets it apart from the competition - 2 ½ times distillation. While they would like to believe that this practice has gone on for the entire 184 year history of the distillery, and there is no evidence to the contrary, no one really knows for sure as the records simply don’t go back that far. There are three stills, the Wash Still, the No. 1 Low Wines Still, and the No. 2 Low Wines Still. It gets complicated if you try to figure out the exact volumes or percentages of what goes where, so I’ll try to explain it as simply as I can. The Wash Still isn’t big enough for the entire 21000 liter contents of a washback, so two runs of 10500 liters go through the Wash Still for each cycle. 60% of this liquid goes out as waste (Pot Ale), and the remaining 8400 liters is collected in a holding tank called the Low Wines Receiver. This liquid is then split up, with 6850 liters going into the No. 1 Low Wines Still, and 1550 liters going to a tank called the Low Wines and Feints Charger. The second still is fired and the low wines are distilled down (stopped at 1% abv, like the first still, I believe), with the distillate collected in the Feints Receiver tank, where it is mixed with the heads and tails that were cut from the third still on the previous run. The contents of the Feints Receiver are pumped into the Low Wines and Feints Charger, mixing with the 1550 liters of Low Wines that were separated of from the output of the first still. All of the liquid in this tank goes into the No. 2 Low Wines Still, for the third and final distillation. The heads and tails are cut out and set aside to be redistilled in the next cycle. The middle cut comes out to an average of 70-72% abv, and will be diluted down to 63.5% abv when it is put in casks. I guess if you wanted to get technical about it, you could say Springbank is distilled 2.8 times, but that’s really nit-picking. As mentioned previously, the single malt under the Longrow label goes through a traditional double distillation, and the Hazelburn brand is triple distilled.
And with all of that information swirling in my head, I was ready for a drink or two at the end of the day – back to the Ardshiel! I was in a Springbank mood, and noticed a Murray McDavid bottling amongst the others. Closer inspection revealed a 9yr old, finished in white wine casks; a risky endeavor, but my curiosity had to be satisfied.
It was interesting, but I didn’t love it. I guess I would call it an exercise in mediocrity. After that I moved on to more of a sure thing, an 11yr Springbank Local Barley bottling. I had nosed the bottle a night or two before, and the intense aromas now drew me back for a dram. It was on the expensive side at £15, but well worth the price of admission.