Bently Heritage: Mixing old and new in Minden, Nevada By James Ludford-Brooks and Johnny Jeffery

Introduction Bently Heritage Distillery is the brainchild of owner and visionary Christopher Bently.

Chris grew up in Minden and set his mind on offering something back to Minden town.

Building a distillery was a natural fit with his ranch, which could offer the malt and grain

to produce the wide range of spirits Bently Heritage Distillery now has planned. The

project is an interesting mix of old and new. The distillery equipment and engineering is

modern, automated and includes a number of novel features to reproduce traditional

practices designed to achieve a distinct character. This new multi-spirit distillery will be

housed in two iconic and until recently, derelict Minden buildings: the Minden Flour Mill

and the Creamery (Minden Butter Manufacturing Company Inc.). The malt distillery will be

built in the Mill Building and the grain distillery located in the Creamery. The Creamery

will also house the malt whiskey casks, the filling and disgorging system, and some

product storage.

John Jeffery, Head Distiller at Bently Heritage Distillery, and James Ludford-Brooks,

Process Engineering Manager at Briggs of Burton have put their heads together to provide

you with an overview of the project to date. Briggs has a long history and reputation for

providing state of the art mashing equipment. More recently this has extended to both

batch and continuous still house design and spirit handling, involving a number of

innovative solutions for significant energy reduction and overall sustainability. As part of

the Bently project, Briggs has provided a number of bespoke equipment designs including

a grain cooker for the Creamery and an external wash heater, or Calandria, on the wash

still, which will sustainably and safely recreate the direct fired character sought by Chris

and Johnny. Below is an overview of the project and some of the interesting engineering

designs and challenges faced in mixing old and new.

Fitting it all in Designing and equipping the existing Minden Flour Silos with a modern, fully

automated single malt whisky distillery has been no mean feat. In essence 4 Silos of 21 ft

diameter by 50 ft contain the entire production process from mashing to new make spirit.

To maintain the integrity and history of the building, the silos have largely been kept

intact except where some reinforcement was required to house the new equipment. It is

interesting to note that a distillery is quite a hot environment with all the cooking and

distillation operations. The still house ventilation is managed by routing all the associated

ventilation pipework through the silo roof, gable walls and facias. Putting pipework

through the silos would have detracted from the overall project’s aesthetics. Other

considerations include the vessels that have been designed to fit the curved walls without

intruding too much into the space, and stacking of equipment such as heat exchangers to

make best use of the height, all without compromising maintenance access. Extensive use

of Briggs in-house 3D modelling capabilities have been used to define the overall

installation concept and allow coordination of all the trades that contribute to the

project, into a single coherent and aesthetically pleasing design. Hopefully you can see an

example of this in the pictures of the flour mill silos housing the grist bin, mashing

equipment, fermenters and two pot stills.

In addition to the production space, a large portion of the Mill Building will be

dedicated to tasting room and retail, with bottle sales and tastings to take place on-site.

The character of the 19th century flour mill will be maintained so the visitors’ experience

will give a sense for the historic nature of the site. The tasting room area in the Mill will

allow viewing of the copper Forsyth’s stills and production floor. Tours will include both

production buildings, and eventually viewing of the barrels in the state-of-the-art

rickhouses, which will be located at the Bently Ranch. Minden itself, sees a great deal of

road traffic, being situated just 20 minutes from Lake Tahoe, and 2 hours from the

Mammoth Lake and Yosemite parks. The hope is to attract visitors from these locations as

well as from spirits enthusiasts worldwide.

Mashing In and Graining Out Across the road from the Minden Mill is the Creamery building, which contains the

grain distillery that will produce Vodka, Gin, Specialities, Wheat, Rye and Oat Whiskies. To

produce all these different distilled spirits the distillery requires a large variety of

mashbills that include corn, barley, oat, rye and wheat. The malted barley will be

prepared at the Bently ranch using the traditional floor malted process, fulfilling Chris

Bently’s commitment to providing a “from ground to glass” experience. Botanicals for the

gin and vodkas will be sourced locally too, from the ranch and the nearby national forests.

Preparation of all the raw materials for the malt and grain distilleries will largely been

done at the ranch. This decision was driven by the space requirements and aesthetics of

the milling equipment, which doesn’t really add to the visitor experience. People tend to

recognise the mash tun, fermenters and stills. The raw materials for the distillery will be

transported from the ranch by truck and transferred into dedicated grist bins located in

the two distilleries.

In the malt distillery, the Grist Bin has a storage capacity of 4,850 lb. This grist is

transferred to a “Steeles Masher”, which ensures that the grist and water are

homogenously mixed prior to conversion, and allows an effective grain bed to form for

subsequent lautering. The 9’ 8” full Lauter Tun is designed for a maximum cycle time of 6

hr for each batch, although the cycle time is of limited concern on the Bently project. The

real benefit of the full lauter system is that the mechanical rig comprising of arms and

knives can be raised and lowered whilst rotating, which can influence the wort haze

allowing a number of different characters to be emulated from clear to cloudy worts.

Coupled with the calandria on the wash still, this is expected to offer significant capability

in providing different spirit characters. Initially the bed loading will be at a 45 lb/ft2.

However, this can be increased and allows production to ramp up in the future. All the

sparge water is collected through a weak worts tank, which is beneficial in maximising the

total extract from the grain and achieving high alcohol yields, as well accurately

mimicking the Scotch whisky process. It should also be noted that the operation of the

entire process is automatic, providing control and repeatability of the full spirit

production process.

In the creamery a grain cooker is used to process the unmalted cereals for the

production of grain neutral spirit (GNS) used in the Vodkas and Gins, and also for the grain

based whiskies. Enzymes are used to reduce the grain cooking temperature, compared to

more traditional jet cooking based processes. A cooking temperature of 165°F is used with

a combination of endo- and gluco-amylases that will hydrolyse the starch in the grains.

The whole mash is then transferred to the fermenters and distillation equipment.

Yeast and fermentation Converting all the sugars in the wort and mash into alcohol is down to the efforts of

the yeast. At the distillery various dried yeasts are pre-mixed and held in a 13 US gal tank

and dosed in-line after the wort and mash coolers en-route to the fermenters. A

combination of wooden and stainless steel fermenters will be used. The Mill building

housing the malt distillery will use 2,380 gal wooden fermenters. Whereas the Creamery

building contains both 5,500 gal stainless steel fermenters for the production of grains

neutral spirit (GNS) and wooden fermenters of the same size used for the oat, rye and

wheat whiskies. The mixture of fermenter construction materials is designed to cater for

the different spirit types, where the porous nature of wood is recognised to harbour

resident microflora that can contribute to the fermentation. From an engineering design

perspective the stainless steel fermenters will have a sealed top with wash viewing

window, manway, and side entry agitator. The fermentation temperatures will be managed

using chilled water through an internal cooling coil, which is important during the summer

to accommodate the high ambient temperatures and allows processing of high gravity

mashes. Fermentation times will be ≤ 95 h and expected to achieve an 8 % ABV prior to

distillation.

Distillation The Bently site will be equipped with two separate and unique stillhouses designed and

engineered by Briggs for the head distiller to practice his craft. For the Mill, Chris and

Johnny had a very specific style of malt whisky in mind. After much sampling their

ambition was to be able to recreate rich, caramel spirit characters usually obtained from

direct fired stills,whilst also designing a stillhouse that is modern, safe and efficient.

During early engineering design reviews the principles of direct fire still heating were

evaluated but discounted due to their noise, inefficiency, and the safety aspects of

confined space working, which all would affect the visitor experience and overall project

vision.

During his time at Briggs, James Ludford-Brooks has worked on a number of distilled

spirits projects, specifically reviewing still house design, safety, and opportunities for

energy recovery. He has also been extensively involved in the brewing industry working on

projects involving mashing equipment and external wort heaters. He was very familiar

with the production of caramelisation and maillard reaction products such as furfural in

the brewing industry when wort is boiled excessively in the wort kettle. It was noted

during some background research that maillard reaction products are significantly reduced

in stills heated with low pressure steam at less than 30 psig steam. He therefore applied

his experience and devised a novel external still heater or calandria using a thermal fluid.

The calandria uses a closed loop heating oil to heat the still externally via a recirculation

loop. This allows operation at high temperatures without suffering from excessive fouling

and film boiling prevalent in similar steam systems, as well as eliminating significant flash

steam loss usually present when utilising high pressure steam in atmospherically vented

condensate systems. The Bently calandria represented a significant challenge both in

process and mechanical engineering terms as the system needs to accommodate

significant expansion and contraction over each production cycle. Safety was also a prime

concern, allowing operation of the fluid at low pressure (30 – 45 psig), opposed to steam

at 145 psig. A picture of the calandria in Briggs workshop is shown.

The Mill employs an energy recovery and storage system via multi-pass condensers and

dedicated sub-coolers, allowing recovery of hot water for still and water pre-heating

during production and also Cleaning In Place (CIP). The hot water circuit allows rejection

of any excess energy via fin fan coolers rather than cooling towers, which significantly

reduces the distillery water and chemical usage. The creamery contains a fully integrated

and automated still house comprising of Headframe Spirit continuous stills and Carl batch

stills, which gives a very flexible plant, capable of providing a wide range of distilled

spirits.

Final Word Everyone is excited to see the Bently Heritage Distillery project developing,

particularly Chris who is starting to see his vision come to life. Johnny has a lot of ideas

for the different spirits planned and is keen to get his hands on the new equipment.

Producing so many different types of distilled spirits across two historic buildings is a

dream come true for the Bently Heritage Distillery team. The Briggs team have enjoyed

the challenge of designing and building a modern and energy efficient distillery in two

beautiful old buildings. All parties involved in the project have got to practice their craft

and will be keen over the next few months to get all the plant equipment installed and

commissioned. The overall project is expected to be completed around Q3 2017 and

Bently Heritage Distillery will be pleased to welcome visitors Q1 2018.

Historic photograph of Mill Building

3D model shots of Mill Building showing the malt distillery contained in the silos

Construction phase with modification of silos in preparation of the equipment

installation

Manufacture of grain cooker in Briggs factory

Calandria for external still heating using oil

based thermal fluid complete in Briggs factory