Crafting Scottish Spirit

Barley is essential for making malt whisky.  Other crops, like corn, are often used in making grain whisky, largely for mass-market whiskies, but typically produces a much more inferior spirit.  

Varieties of Scottish two-row barley has been developed for brewing and distilling and produces higher levels of fermentable starches than crop barleys used for livestock feed.  Besides the starch , The barley seed also contains important enzymes that are required to break the starch down into fermentable sugars.  These fermentable sugars are metabolized by the yeast during fermentation. 

Harvested barley is steeped in large vats of water then spread out upon a large 'malting floor', where this green barley is regularly turned over to encourage the grains to sprout.  

Once the grains begin to sprout they are placed into a malting kiln, where they are gently heated up to stop the sprouting process.  When the germination process is stopped,, the barley is then known as 'malt'.  

At this stage, many distilleries may add peat to the kiln in order to impart desirable smokey flavors into the malt.  Peat is a fuel source that was created over thousands of years of decaying plant and animal settling into bogs in Northern hemisphere ecosystems.  These ecosystems feature different plant species, so there are pronounced regional differences in the flavors that peat can impart.  It has been used for centuries as an important fuel source to heat homes in the treeless highlands and Western islands of Scotland. 

The malted barley is then taken from the kiln, ground into grist and then added to a mash tun where it is 'cooked' in hot water in order to release the fermentable sugars inside the barley grains.  Mashing separates these desirable sugars out of the grains, and the resulting wort is sent to large washback tubs where it is cooled down to a point where distiller's yeast can be added and allowed to brew into a sweet, weak 'beer' wash that can be sent to the stills.  The spent grain, known as draf, is not wasted.  It gets used by local farmers to feed animals. 

The distillation process is typically done in two parts: first, the wash is heated to vapor and condensed back into a liquid in the lyne arm of the wash still.  At this stage the resulting liquid is known as 'low wines'  and is about 20% alcohol.  These low wines are distilled into vapor a second time and condensed by the lyne arm in the spirit still which creates a distillery's new make spirit.  This second distillation increases the distillate to 60-65% alcohol.  

The distillates (liquids collected after condensing) pass through a distillery's 'spirit safe' where they are monitored for quality.  As distillation progresses, and a run of alcohol happens, there are three 'cuts' made from the spirit still:  the first liquids to be produced in the beginning of the run are known as the heads, or foreshots.  These are poisonous and removed from the run, and sent to the feints receiver.  The middle or heart is the desired alcohol product and sent to the Intermediate spirits receiver to eventually be casked for maturation.  The tails, or aftershots, or feints is the end of the run and contains bad flavors.  These are also sent to the feints receiver.  The master distiller is the person who 'calls the shots' as to which part of the distillate to keep and which to reject.  

Copper is used extensively for constructing stills because a) it is a common metal and easily shaped, b) it is a good conductor of heat, c) its chemical properties act as a catalyst for speeding up reactions, and d) it reacts with compounds in the gaseous phase to remove sulphur containing compounds.  The shape of the stills and their Lyne arms is engineered to affect the final flavors of the new make spirit. 

By law, in Scotland, malt or grain whisky must be matured in oak casks for a minimum of three years.  Oak wood is used almost exclusively to age new make spirit as its cellular nature has structures known as tyloses which effectively make casks water tight, yet allow for transfer of vapor.  White oak is most desirable for its liquid retention and for its spicy or peppery flavors.  

There are many soluble compounds from the oak wood that are imparted into the spirit at different stages of maturation.  These compounds provide aroma, flavor and color in the final whisky.  In the Scottish whisky industry, there are two types of Oak that are primarily used:

• Quercus alba - American white oak
• Quercus roubar - European white oak

In the United States, by law, all bourbon must be made in new charred oak barrels.  Whisky makers in Scotland take full advantage of this law by buying up lots of spent bourbon barrels to mature their new make spirit in.  

European oak often comes from the wine industry - typically sherry.  Many distilleries in Scotland will begin to mature their spirit in old bourbon barrels for several years then transfer the spirit into used Spanish sherry butts.  Many distilleries will also use port, rum and a variety of wine casks for maturation to impart different characteristics into the whisky.

Several different types of casks are used to mature whisky:

• Barrels - Ex-bourbon, American Standard Barrel = 200 Litres/53 US Gal
• Hogsheads - Made from staves of other casks, common in the sherry industry - 238 Litres/63 US Gal
• Puncheons - former rum and sherry = 320 Litres/85 US Gal
• Butts - Port and Sherry = 500 Litres/132 US Gal 

Whiskies matured in different casks  may be combined together at the distillery, then replaced into different barrels and aged for additional time.  This process is known as the marriage and 'honeymoon' period where the final flavors are matured into the  expression desired by he distillery's master blender.  Most distilleries send their casks or bulk tankers offsite to specialist bottling facilities. The whisky is transferred to a vat after being filtered to remove any solid from the casks.  Some operations leave the whisky to 'marry'' in the vat to homogenize.

Before bottling, the whisky must be reduced to bottling strength, unless a cask strength product is being made.  The alcohol content is reduced by adding de-ionized water to ensure no flavors or taints are added.  To legally be considered whisky, the alcohol level must not drop below 40%.  Higher alcohol levels deliver more flavors than lower strength whiskies. Some distilleries will add caramel color (E-150A) at this stage in order to homogenize the look of their product.  This is an aberrration and typically found in mass market products.

Another aberration is committed by some distilleries before bottling - chill filtration.  this process is done to prevent whisky from becoming cloudy if exposed to cold temperatures. The cloudiness is due to larger  molecules like long-chain fatty acids and esters (key components of flavor) coming out of suspension due to sharply reduced temperatures.  A distillery will quickly chill the whisky down to between 0-4 degrees Celsius then filter out the fatty molecules.  

We believe that the most desirable whiskies are bottled at cask strength without added caramel coloring or chill filtration.