The very first step is to immerse the selectively picked barley in water for 2 to 3 days. Once the barley has absorbed enough water and oxygen, it will start to germinate. The aim is to convert the starch into glucose, which will be absorbed by the yeast to proceed fermentation. Most distilleries will immerse the barley once then drain, and add water again. Water temperature and time control depend on the weather and habits of every distillery.
Steeped barley will germinate when exposed to air. This process is all about time control. Short air breaks will lead to insufficient malting and affect the final amount of whisky produced. While a long one will produce toxins and destroy the whole batch of barley. In the past, the old Scotch distilleries would put the barley on the floor and turn them from time to time. It took a week to finish malting.
Perfectly germinated barley needs to be dried to stop further germination. Scotch distilleries used to mix peat with other fuels during kilning, that’s why old Scotch whisky always has the strong peaty and smoky flavour. Nowadays there are more ways for kilning. To produce an ideal peaty flavour takes meticulous planning on adjusting the proportions.
Dried barley must be grinned before mashing. It’s crucial to control the size of grist. If the grist is too coarse, fermentation will be lowered; if it’s too fine, it will clog up the mash tun when filtering. Therefore, the size of grist depends on the structure of mash tuns.
Mix the grist and hot water then feed into the mash tun. After a while, filter the first round of wort and add hot water again. Then, filter the second round of wort. These two rounds of wort will be fermented later. Add hot water again and filter the third round of wort, which will be used to the first waters for the next round of mashing. Since the remaining draft is very nutritious, most distilleries will sell to feed producers or farmers. It takes 8 hours for a batch of barley to mash, varying according to temperature and humidity in the year.
Wort is filled in wash backs and fermentation begins once yeast is added. The yeast cells will convert the sugar into alcohol. Owing to the difficulties of fixing and cleaning, most Scotch distilleries are using stainless steel wash backs to replace the old wooden vessels. Believing that whiskies fermented in wooden wash backs have richer flavour, some distilleries insist on following the tradition. Talisker, whose average fermentation takes around 50 hours, is a good example. Wishing to bring a stronger fruity notes and soft texture, Glen Ord, which produces The Singleton Single Malt Whisky, insists on long fermentation for around 75 to 80 hours. This is the double of average fermentation time of other distilleries.
Distillation is the most diverse and complex process. Basically 90% of distilleries adopt double distillation. Fermented wash will be put into the wash still for first distillation, then transferred to the spirit still for second distillation. The cut will be extracted for further maturing, while the foreshows and after shots will be collected. They will mix with the next batch of wash and distill again. Each distillery has its own cut point, according to its cost and own character. The alcoholic strength after the second distillation is around 70 to 85%.
The Scotch Pot Stills use copper to absorb the unwanted impurities in the wash, producing pure whisky with high ABV. The design and structure of each still plays a key role in whisky flavour. Its size, shape, height and angle of Lyne Arm, way of heating and setting of condenser will all affect the flavour of whisky.
To create its exclusive smooth and rich texture. The Singleton uses copper stills and adopts slow distillation, allowing more impurities to be absorbed.
After double distillation, the diluted new-make spirit, mostly with 63.5% or 68% ABV, will be placed in oak casks to mature. Bourbon and sherry casks are commonly used. The quality of casks, the cellars’ temperature and humidity are all crucial factors to affect maturation. In Scotland, due to its climate, alcohol evaporates faster than water. That’s why the longer maturation, the lower ABV a whisky will have. And the percentage of liquid evaporates annually from a cask is called Angel’s share.
The Singleton mainly uses bourbon and sherry casks. Toasted and charred bourbon barrels can especially bring out the vanilla and caramel flavour. Old European oak casks seasoned by Spanish sherry can bring out the sweet fruity note and silky round texture.
Before bottling, most whiskies will be blended by whiskies matured in different casks, but single cask whisky will be bottled directly. It is worth noting that now many distilleries choose to outsource the bottling process.
Being a blender for over 40 years, Maureen Robinson is one of the best in Scotland. She subtly mixes two types of casks and creates a harmonious taste. She has also created an irresistible perfect palate, which ignites your taste buds with rich layers of flavours.Back