When we first set out to build a brand new distillery in the heart of the Cotswolds, we knew we wanted to use the best possible kit, traditional methods and the highest quality raw ingredients. Thankfully we had the guidance of renowned industry legends Harry Cockburn (former Distillery Manager at Bowmore, with many decades’ experience in whisky making) and Dr Jim Swan (fondly known as ‘the Einstein of whisky’ for his formidable knowledge of the science of distillation and maturation). With their help, our small distillery team began production in September 2014.
We begin at the farm. Right from the start, we committed to using only local barley – all the barley that will ever go into our whiskies will have been grown here in the Cotswolds. And each bottle will state the farm it originated from on the label.
The harvested barley heads to the maltings at Warminster, Britain’s oldest working maltings. Using the same techniques they’ve used for hundreds of years, the maltmen steep the barley, before turning it on the malting floors by hand for several days. 100% of the malt we use is traditionally floor-malted. The final step is to kiln dry the malt and then send it up to us at the distillery.
First thing in the morning we get started grinding up the malt in our mill, so that we can extract the fuel inside it more easily. The ground-up malt, known as grist, falls directly into our 0.5 tonne mash tun where we mix it with hot water in three stages. The heat of the water triggers reactions in the malt that release its sugars into the water, turning it into worts.
We run the worts off into one of our 8 steel washbacks, collecting 2,500 litres from one mash. We then add two strains of dried yeast. These were selected not just for their consistent yields but more importantly, for the excellent flavours they produce. This live yeast will turn the sugars in the worts into alcohol. We let this fermentation continue for just over 90 hours – this is considerably longer than the average fermentation length in whisky production. In the first two days of the process, the yeast works hard to produce alcohol and the wash will reach a peak of about 8%ABV. After that however, no more alcohol will be made, so most distilleries finish their fermentation there. But if left to continue for a third and fourth day, a secondary stage takes place in which the wash fills with bacteria. Although it makes it look and smell rather odd, we want this to happen – the bacteria produce acid, which combines with alcohol to form fruity flavour compounds called esters.
This was one of Dr Jim Swan’s masterstrokes – making sure that the wash was loaded with esters that would give our spirit a fantastic fruity complexity.
On day 5, we’re ready to start distilling and the first step in our double distillation process is the wash still – otherwise known as Mary. She’s a 2500-litre copper pot still, made for us by Forsyths in Rothes. By boiling the fermented wash for several hours we can collect the Low Wines; liquid containing all the alcohol and flavour compounds from the wash.
We then need to pick out the best bits from the Low Wines – only these will make it into the spirit and become whisky. To do this, we distil the Low Wines in the second still: our 1600-litre spirit still, Janis. The first liquid to run off the stills is the harsh ‘foreshots’, which are set aside. These are followed by the ‘heart’ of the run – our future whisky, which is collected for only a couple of hours before the spirit flowing off the still becomes heavier and oilier. This is the final section, called the ‘feints’ and this is also set aside.
Our cut points (the moment we switch from foreshots > hearts > feints) are also quite unusual. The fruity esters created during fermentation will appear very early on in the distillation, so in order to capture them in our spirit we make sure we switch from foreshots to hearts after only a few minutes. The cut to feints also happens sooner than it usually would – this means that none of the heavier, rougher compounds that come through towards the end will make it into our spirit.
The heart cut, a colourless and fruity spirit, is known as new make spirit, and it is at 75% ABV. Thanks to our unusual fermentation and cut points it is already smooth enough to drink and full of flavour, not all that different to a grappa or eau de vie. We reduce this to 63.5% by adding demineralised water, and then it is ready to be casked. We fill the spirit into an oak cask, and then place it in the warehouse, where it will rest for a minimum of three years and one day, but potentially longer.
Over time the spirit will mellow and smooth out, and flavours and colours will be drawn out of the wood. We are filling a range of different types of cask and these will all produce different tasting whiskies. Once mature, several casks will be selected to be blended together in a batch, with each cask introducing different characteristics. The whisky is then reduced to its bottling strength of 46% and bottled here by hand at the distillery.
To make our gin, we begin with a base alcohol made from wheat. This ‘neutral grain spirit’ (supplied to us by Haymans in Essex) is at 96% ABV and is completely flavourless. It is the blank canvas that we will add flavour to through our recipe of botanicals.
We place the neutral spirit and some water into our copper pot still, made by Arnold Holstein in Germany. It is a 500-litre pot still, but we only fill it ¾ full to make sure the vapours get plenty of contact with the copper during distillation. We then add the base botanicals (including the all-important juniper berries) and these macerate for 15 hours overnight.
In the morning, we add the rest of the botanicals to the still. We use about 10x the average weight of botanicals for a premium gin and it’s the quantity of essential oils and botanical extract from them that gives our gin its characteristic richness.
Then we begin distillation, slowly boiling the contents of the still to drive off the vapours containing all the alcohol and the flavours. The first liquid to appear is called the ‘heads’ of the run – it is quite harsh and astringent, and is discarded. The middle or ‘heart’ of the run is the only gin we will use, and we run that off the still very slowly. The final section of the run is the ‘tails’ and these are also discarded. Similarly to the cut points of our whisky, the gin heart cut happens early in the run and is relatively small – we’re just selecting the finest part of the run and avoiding any impurities. It means we only make a very small number of bottles from each run of the still, but the quality is fantastic.
The hearts, which are at 83% ABV, are then rested for 5 days to allow the various flavours to come together and settle in – nothing is rushed. All we then do is add filtered water to reduce the strength to 46% and the gin is then bottled here at the distillery. This is known as ‘single-shot distillation’ and it means we don’t add any more neutral grain spirit to the distilled batch to stretch out the gin and increase the number of bottles made from each run. Single-shot distillation is certainly a less efficient way of making gin, but we think it ensures the best possible flavour and quality. We also don’t believe in chill-filtering our gin; this process removes oils and esters to make sure the gin stays crystal clear. We decided to leave the gin unfiltered, to guarantee a rich and robust mouthfeel, meaning a pearlescent ‘louche’ appears when you add ice or tonic.
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Welcome to The Cotswolds Distillery
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