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.
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