What is floor malting?

In floor malting, the barley goes through three steps: soaking in water, germinating in a thin layer on a floor, and drying in a kiln over a fire.

Steeping gets the grain going. The Scotch Malt Whisky Society describes periods of immersion and air rest over two to three days. Kilchoman keeps the steeping water at 12 to 16 degrees Celsius and works towards a moisture content of 43 to 45 percent. The damp barley then goes to the malting floor, where the grain forms rootlets and a small shoot. As soon as that shoot has reached about three quarters of the grain length, Kilchoman stops the process by kilning: drying the green malt, so that the conversion of starch does not go any further.

A floor maltings needs ten to eleven days for a batch, against about eight days at an industrial maltings, writes trade magazine Whisky Magazine.

The steps are the same for both, but on a floor everything is done by hand and is therefore slower. According to the Scotch Malt Whisky Society, germination takes four to five days and kilning 20 to 48 hours, with the kiln first at 55 to 65 degrees and then rising to 70 to 75 degrees. Springbank gives 30 to 48 hours for its own kiln, and Whisky Magazine arrives at three to four days for distillery kilns. The difference lies mainly in how much peat is burned and how long drying continues.

Turning keeps the layer airy and the temperature even, so that all grains germinate equally fast and the rootlets do not grow together.

On the malting floor the barley lies in a layer of limited thickness. Springbank spreads an even layer of six inches, about fifteen centimeters, and turns it at fixed times. Kilchoman turns the layer by hand every four hours and adjusts the thickness of the bed to the season, to control the temperature of the grain. The tool is a wooden shovel, called a malt shiel in Scotland. Without turning, the bottom layer would get too warm and the grains would grow together into a mat.

The Scotch Whisky Regulations 2009 prescribe that Scotch whisky is made from water and malted barley, to which only whole grains of other cereals may be added.

That regulation says nothing about the way of malting, so floor malting is not a legal requirement but a choice of the distillery. It does state that the mash is made at the distillery itself and that the conversion to a fermentable mash happens exclusively through enzymes from the grain itself. Added enzymes are therefore not permitted, and so malting is the only route to those enzymes. The regulation further demands fermentation with yeast only, distillation to below 94.8 percent alcohol, maturation of at least three years in Scotland in oak casks of at most 700 litres, and at least 40 percent alcohol in the bottle.

The Edinburgh Whisky Academy counts nine Scottish distilleries with a working floor maltings on their own site.

On that list are Springbank, Balvenie, BenRiach, Bowmore, Highland Park, Laphroaig, Kilchoman, Glen Garioch and Dunphail. According to that source, Springbank malts one hundred percent of its own barley in Campbeltown, Bowmore about thirty percent on Islay and Highland Park around twenty percent on Orkney. Balvenie calls itself the only distillery in the Scottish Highlands that still grows and malts part of its own barley itself. Glen Garioch brought back the floor maltings during a refurbishment costing six million pounds. Kilkerran comes from the neighbouring distillery Glengyle and uses malt from the floor maltings of Springbank. Whisky Magazine points out that most distilleries switched to industrial maltings in the sixties and seventies, which could compete with highly automated production on a cost item that makes up 55 to 60 percent of the total.

In the whisky section in Bathmen there are 233 bottles from the nine Scottish distilleries that do their own floor malting, spread over nine brands.

These are Kilchoman with 58 bottles, Bowmore with 35, Highland Park with 28, Laphroaig with 28, BenRiach with 21, Balvenie with 19, Glen Garioch with 17, Springbank with 16 and Kilkerran with 11. All nine come from Scotland. The alcohol percentage ranges from 40 to 66.4 percent, from regular bottlings to cask strength. The whole whisky shelf comprises 3,898 items, so this group is a small part of it. Anyone who wants to find out what a distillery's own floor maltings does to the end result can line up bottles of these nine side by side in the shop.