Making Kirkwood Distillery's spirits is a lengthy process, and not all of it happens at the distillery.
In the diagram below, you can see all of the end-to-end steps needed to complete the process.
Growing
Maris Otter barley is highly regarded by artisan distillers. Rye may also be used.
Malting
Malting softens the barley and makes the starches accessible to the brewer without the need to add enzymes. It gives the spirit body.
Mashing
Mashing in hot water converts the starches into fermenting sugar
Fermenting
Yeast is added, converting the barley sugar into a distillers 'beer'
Wash Distilling
A first distillation in Kirkwood Distillery's pot still strips the alcohol from the beer and produces a liquid of about 30% ABV
Spirit Distilling
The second distillation in Kirkwood Distillery's reflux column still with 30 equivalent plates further refines the alcohol to 96% ABV for gin and vodka, and less than 94.8% if making English whisky or rye.
Filtering
The spirit is filtered through activated charcoal to remove any impurities
Gin Rectifying
If Kirkwood Distillery is making distilled gin, the spirit is 100% redistilled through a reflux chamber where the botanicals are vapour infused. They use a single-shot method where just enough botanicals are used and don't add neutral spirit after, so that it is properly distilled gin.
Resting
The gin is rested for 3 to 4 weeks allowing the full flavour to develop
Bottling
Finally, the spirit can be bottled to be sold and enjoyed in fine cocktails
By comparison, most gin distilleries these days don’t bother with all of these steps.
Most modern gins are made using bland sourced spirit to which they add a concentrated distillate.
Growing
Maris Otter barley is a classic UK variety highly prized by brewers
Malting
Malting softens the barley and makes the starches accessible to the brewer
Mashing
Mashing in hot water converts the starches into fermenting sugar
Fermenting
Yeast is added, converting the barley sugar into a distillers 'beer'
Wash Distilling
A first distillation strips the alcohol from the beer and produces a liquid of about 30% ABV
Spirit Distilling
The second distillation further refines the alcohol of absolute purity of 96% ABV
Filtering
The spirit is filtered through activated charcoal and then fine filter papers to remove impurities
Buy sourced spirit
Rectifying and compounding
Some of the spirit is redistilled in a pot still, where the botanicals are often boiled rather than vapour infused, making a concentrated gin distillate, which is added to sourced spirit and water. If it's called distilled gin, this method is forbidden, and the entire spirit is redistilled with water and botanicals to at least 70% strength, then watered down.
Resting
The gin will possibly be rested.
Bottling
The spirit is bottled
Making the Barley Wash
Kirkwood Distillery takes an un-hopped distiller’s beer of 7% ABV. The beer wash is fermented slowly at a low temperature to prevent any awkward flavours from developing that might concentrate during distillation.
Wash Distillation
Kirkwood Distillery's first distillation is called a stripping run, as it strips the alcohol out of the raw beer in a pot still employing some reflux with copper and stainless steel springs. The resulting low wines are 30%ABV.
Spirit Distillation
The second distillation uses the more high-tech reflux column still, equipment not typically available to gin makers, during which the spirit undergoes roughly thirty equivalent distillations in one long process called fractional distillation. It takes three days to produce a spirit of up to 96% ABV, the strength depending on how the distiller controls the input energy and output flow according to the desired style of spirit.
Filtering
The distiller pumps the spirit through activated charcoal for several hours to remove any trace impurities. Charcoal is favoured for filtration partly because of the large surface area and its porous nature, which binds to impurities, particularly volatile organic compounds. This also explains why casks are burnt on the inside to provide a layer of charcoal. At this point the spirit can be blended with purified water, rested, and bottled as Kirkwood Distillery's award-winning Barley Vodka. For gin a few more steps are required. After all of the hard work and nearly four weeks after the grain was first mashed, the distiller arrives at the starting point for making a gin.
The authenticity of seeing the spirit all the way through the process gives a much greater sense of provenance to the final product.
Gin Rectifying
To make the spirit into gin, the distiller adds botanicals which are placed in a muslin bag and soaked in the spirit overnight to macerate. The next morning, that bag of soggy berries, blossoms and peels gets suspended inside the column of the still, the boiler is started, and the flavours are vapour infused into the spirit in a process taking most of the day. Distiller's ceramic discs are packed in the lyne arm to provide reflux, which maintains a higher alcohol content throughout the distillation, compressing water vapour into the tails.
Resting
Gin needs time to rest after it’s made. The flavours need time to meld and solidify into the final taste. Some botanicals take longer than others to mature, and the character of the gin changes quite dramatically during these important weeks of resting. A gin tasted the day it is made will be entirely different after several weeks of resting, so this vital part of the process cannot be rushed.
Bottling
Finally, it’s time to put the spirit into bottles. At this point, it will have been over two months end-to-end in the making, and every bit of effort and every hour of hard work has resulted in an exquisite liquid.