How to Build a Washback

IN

Our newest washback for fermenting the worts was installed this week. The sounds of synchronised tamping, and the physical teamwork involved – bending metal and handling wood – make it feel like we’ve had a medieval guild staying. A bespoke Oregon pine (Douglas fir) vessel, 13 feet tall, it is held together just by riveted bands of galvanised steel. And the natural principle that wood fibres swell when they hold water. Just like a giant, open-topped cask.

Inside washback no.5

Ron Lowe and the team from Joseph Brown of Dufftown – which includes his son and apprentice Ross – built the washback on site in the traditional way, and are the only company left in the country that do so.

Ronny himself is a time-served cooper. It takes four years to become one, though he says to learn vat-building takes longer than that because of the scale, and the fact, “Every job is different!” What about the Bruichladdich job then?  “It’s an excellent tun room to work in, it always is. That’s why it’s so good to work here, and the staff helps, everyone’s very accommodating.”

With the correct care for the timber, each washback should see 60 years of use. The alternative would be to use stainless steel vats, which last almost forever, and are easier to clean. You may not be surprised to learn that at Bruichladdich, however, in Production Director Allan Logan’s words, “We’ve committed to traditional.” Not only do we like working with such craftsmen, but “What the wood does is to create the most stable environment for fermentation.” This washback, number 5, in the corner, is part of ongoing renewal, after the building of a new number 4 in 2010, number 2 in 2013, number 6 at Christmas 2017, and number 1 last September.

“We’ve committed to traditional.”

Each washback holds 60,000 litres, but as Allan explains, “We don’t need it to hold 60,000 litres. The volume we get from one mash is 35,000 so then we’ve got the headspace for fermentation.” On any given day at the distillery, you can slide back the heavy timber tops and see and smell the yeast, in various stages of its work converting the sugars from the malted barley ‘worts’ into alcohol. The mashmen check the level of alcohol with hydrometers throughout the fermentation period. By the time it goes through to the stills, it’ll be ‘wash’ at between 5 and 6%.

The new washback won’t be ready to use immediately. “Now what we’ve got to do is fill it with water,” Allan explains. “Douglas Clyne, our engineer, is just fitting the discharge onto it, the pipework, and then we’ll leave the base with maybe 6 inches in the bottom of the washback, for about 6 – 8 hours, just to let the base soak in that water. Then we’ll slowly fill it over the course of about 5 days, just slowly, enough to let the wood swell up. You don’t want to put too much weight in it, to begin with, ’til it settles. You want to let the wood swell from the bottom up. “

Teamwork in the tun room

“Next, the gauger Bob comes in and he’ll calibrate the vat. Because, basically, it’s handmade, there’s natural variation, so it’s not going to be exactly the same as the other ones. So he’ll calibrate it and give us charts based on the size and dimensions of that vat. Then, when we dip it with the shoulder rod (which is like a massive ruler) to get the depth measurement, the corresponding volume of liquid in there will be absolutely accurate.”

The only computers involved are the ones that precision-control the sawing of the beautiful wooden staves, back at the beginning in Dufftown. As with anything to do with whisky, we approach it with patience, and with people power first.

You can watch a timelapse video of Ronnie & co building a previous one of our washbacks here: 

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