How Peat Is Cut and Burned for Malting
At Bowmore, the maltman spreads broken peat over the fire to keep it smothered. The aim is smoke, not a roaring blaze. That smoke rises through a mesh kiln floor into the barley above: the final stage of a fuel's journey from wet bog to cut turf, dried peat and kiln fire. [1][4]
What peat contributes to malting
“Peat reek” is the distinctive aroma carried by peat smoke. The Scotch Whisky Technical File describes peat as turf cut from Scotland's moors and used as a natural fuel for drying malted barley, alongside more modern fuels. Its account follows the smoke upwards through a wire mesh floor. [1]
Picture peat below and barley above, with smoke passing between them. Historically, peat also fired the stills, according to the Technical File, but that was a separate use from burning it beneath a malting kiln. For the wider barley process, start with how malting works. [1]
How peat is cut
Traditional hand cutting starts by stripping away the vegetation. Visit Outer Hebrides names this surface layer am barr fhad and describes the tool used beneath it: a tairsgeir, with a long wooden handle and an angled blade, which cuts the peat into slices. Its account describes each property's allotted peat bank, often bearing an old Gaelic name. [5]
Hand cutting is only part of the whisky peat supply story. A 2019 Whisky Advocate report described most peat as machine cut; the 2026 guidance from the Scotch Whisky Association, SRUC and SEFARI Gateway sets out several harvesting methods. The important distinction goes beyond hand tool versus tractor, because machinery can extract and shape peat in different ways. [2][4]
| Method | What happens | Drying described by the source |
|---|---|---|
| Hand cutting | Surface vegetation is stripped, then slices are cut with a hand tool. | Laid out, lifted into small “houses”, then stacked. [5] |
| Adapted extrusion | Tractor driven machinery draws a pipe or “sausage” of peat from below the surface. | Laid on the bog to dry. [2] |
| Block cutting | Saturated peat is cut into blocks. | Air dried on the bog for months. [2] |
Why drying comes before burning
Freshly cut peat does not go straight into the kiln. The 2026 guidance describes block peat drying in the air for months, usually bringing its moisture content down from 90% to 40 to 60% before use. Larger blocks generally dry more slowly than smaller extruded pieces. The form in which peat is harvested matters as well as the time spent drying. [2]
The Hebridean hand cutting account gives that drying work a distinctive outline on the moor. Slices lie out for up to two weeks, then are lifted into small “houses” to expose the other side. Next comes the cruach, a tapered stack about 2 metres high. Its taper helps keep the peat dry. Cutting, drying and stacking are separate stages of the job. [5]
Weather and season set the pace. Kilchoman says peat cutting on Islay normally runs from around mid April through to July. The 2019 trade report describes peat standing to dry by June or July, being stacked for further drying, then gathered into the barn by August. This is the rhythm of the Islay practices described, rather than a calendar for every peatland. [4][6]
How peat is burned for malting
Bowmore's own process description places two furnaces beneath a mesh floor, with smoke passing upwards through the barley. The 2019 trade account supplies the working detail: both furnaces are lit, then the maltman spreads peat caff, meaning broken peat, over the fire to smother it rather than let it roar. [4][9]
The work is a matter of tending smoke, not building the brightest fire. In that Bowmore account, the fire is checked hourly and the malt turned every four hours. Wind changes the routine: the report describes around four scoops of dry peat for each scoop of caff on windy days, with a peat fire lasting 18 to 21 hours as conditions vary. These are Bowmore's recorded practices from 2019, rather than operating instructions or standard settings for other kilns. [4]
Laphroaig calls its approach “peating and cold smoking the barley”, a more useful image than grain roasting over an open blaze. At Kilchoman, smoke exposure is only part of the drying programme: its published malting account separates the peat fire period from a further period of hot air drying. [8][10]
How smoke reaches the barley
The barley is still moist when the smoke reaches it. Kilchoman describes phenols rising through the kiln in that smoke and attaching to the grain above. In its explanation, longer exposure to the peat fire increases the phenol level measured in the malt. Here, ppm means parts per million in malted barley, not in the whisky eventually bottled. [7]
Kilchoman's March 2024 account gives 10 to 15 hours over the peat fire for its 20 ppm malt, followed by another 20 to 30 hours of hot air drying. Its earlier explanation, published in 2018, gives an average of 10 hours for that malt. These dated accounts describe the producer's own process; firing time alone is not a formula for a guaranteed ppm figure. [7][8]
Springbank also describes drying over peat, hot air, or a combination of both, depending on the spirit being made. Its published duration of 30 to 48 hours covers that drying process, rather than specifying a separate period of peat smoke exposure. [12]
Why the condition of the peat matters
Comparisons between hand cutting and machine cutting need to consider the peat's condition when burned, not just the tool that removed it from the bog. The 2026 guidance identifies moisture, particle size and the drying area as factors affecting handling, combustion behaviour and quality consistency. [2]
The same guidance compares harvesting methods by the quantity extracted, their restoration potential and their impact on the site. Tractor extrusion is rated as extracting the most peat, with a medium to high site impact. How peat is removed and how the ground is treated afterwards belong in the account alongside the smoke eventually produced. [2]
Extraction does not end with the harvest
Restoration is one of the 2026 industry guidance's three principles. It says all harvesting must be paired with robust restoration plans. It also identifies a substantial supply concern: the majority of Scotch whisky's peat comes from a single commercial site whose licence holder is considered unlikely to seek renewal. That could reduce mainland supply by around two thirds, the guidance says. [2]
The warning gives cutting and drying a significance well beyond the kiln door. This guidance addresses extraction and restoration, not kiln efficiency, so its harvesting recommendations do not assess how efficiently an individual distillery burns peat. [2]
Reading a malting description
Keep dates beside process figures. Bowmore's reported firing routine is a 2019 observation; Kilchoman's timings come from its own accounts published in 2018 and 2024. These descriptions make the work tangible, but they are accounts of particular producers' practices, not a universal recipe for peating. [4][7][8]
Where to go next
- How Malting Works: follow the barley process around the peat firing stage.
- Floor Maltings: The Distilleries That Still Do It: read about the places retaining floor malting.
- Why Do Scottish Distilleries Have Pagoda Roofs? Charles Doig's Story: explore the story behind the kiln roof.
Sources
[1] UK Government. Technical File for Scotch Whisky, June 2019.
https://assets.publishing.service.gov.uk/media/5fd36667e90e07662ed92c85/Scotch_Whisky_Technical_File_-_June_2019.pdf
[2] Scotch Whisky Association, Scotland's Rural College (SRUC) and SEFARI Gateway. Principles of Responsible Peat Extraction for the Scotch Whisky Industry, May 2026.
https://sefari.scot/sites/www.sefari.scot/files/2026-05/Principles%20of%20Responsible%20Peat%20Extraction%20for%20the%20Scotch%20Whisky%20Industry%20May%202026_0.pdf
[4] Whisky Advocate. McCormick, J. Meet the People Who Make Peated Whisky Possible, 19 August 2019.
https://www.whiskyadvocate.com/people-make-peated-whisky-possible/
[5] Visit Outer Hebrides, Outer Hebrides Tourism. Peat Cutting, 21 September 2020.
https://www.visitouterhebrides.co.uk/blog/read/2020/09/peat-cutting-b36
[6] Kilchoman Distillery. Traditional peat cutting, 2 August 2021. Producer's account.
https://www.kilchomandistillery.com/distillery-news/traditional-peat-cutting/
[7] Kilchoman Distillery. What is PPM in whisky?, 4 December 2018. Producer's account.
https://www.kilchomandistillery.com/distillery-news/what-is-ppm/
[8] Kilchoman Distillery. Behind the Scenes at Kilchoman: Malting, 14 March 2024. Producer's account.
https://www.kilchomandistillery.com/distillery-news/behind-the-scenes-at-kilchoman-malting/
[9] Bowmore. Our Process, undated. Producer's account.
https://www.bowmore.com/our-process
[10] Laphroaig. Tales of Fire, undated. Producer's account.
https://www.laphroaig.com/taste-trailblazers/tales-of-fire
[12] Springbank Distillery. Process, undated. Producer's account.
https://www.springbank.scot/about/process/
This desk research article was prepared from the site's verified fact sheet TOP-A428, distinguishing industry guidance, trade reporting and producers' own process descriptions.
Last checked: November 2026