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Making Malt Whisky

The Scotch whisky industry has done a tremendous job in promoting the mystique of a product which has been produced for centuries and now is worth some £4.67bn in UK exports with the USA alone taking £1.04bn worth. Other big markets are France, Singapore, Germany, Spain and Taiwan. Home sales are worth around £1.1bn.

David Wilkie’s famous painting of home distilling in 1840.

We see bubbling streams from mountain corries cascading over a peat landscape; expert distillers sniff assiduously at the spirit safe to make the right cuts, artisan still makers hammer out copper in the time honoured fashion to mimic the knocks of ages when a distillery needs a new still. The angels are busy in dark, dank, dusty warehouses taking their share from 20 million mainly ex bourbon casks. Blenders nose, sip and spit in front of a table top of samples while some 1.9 million visitors a year follow whisky trails.

Malt whisky making on the British Isles has even spread beyond Scotland. Penderyn in the Brecon Beacons started in 2000 followed by St Georges at Thetford in 2006. There are now 14 in England and three in Wales on top of 128 in Scotland. Clonkilty which opened last month on the Atlantic coast in County Cork is Ireland’s 23rd. Germany is said to have more whisky distilleries than Scotland. Japan makes some pretty good malt whiskies while India tends not to by using molasses rather than malt in cheaper products which still bear the name.

The first reference to distilling in Scotland is in 1494 when monks at Lindores Abbey in Fife got 8 bolls of malt to make aqua vitae. That is half a ton so distilling must have been more than just an experiment even then. Barley grew locally, it rained a lot in Scotland and there was plenty of peat to use as a fuel. There were attempts to limit the size of stills so that revenue was easier to collect at larger distilleries which were situated mainly in the Lowlands. Efforts to help Highland producers by allowing them to use stills below 20 gallons in capacity, provided they only sold locally, led to a lot of smuggling. A duty reduction and a total ban on small stills (which was only raised less than ten years ago) came in during 1823 which made sure that lugging a worm out into the heather for a bit of moonshine making remained a niche cottage industry.

Victorian advertising of blended whisky in 1898. They gave away 500 grey parrots trained to sit on the bar and say ’buy Pattison’s Whisky’! Three years later the Pattison brothers were in prison for making false claims about what was in the whisky. Fine old Glenlivet was not fine, not old nor even Glenlivet!

The pot still was the only method of production but all-malt spirits were deemed to be a wee bit heavy. The 1830s saw the invention of the continuous still which used any sort of cheap grain as most of the product went south for the English gin market. It still does as a lot of the nation’s neutral grain spirit for the current gin boom (sales up 43% on 2017 to 73m bottles) comes from Scotland. Grocers and wine merchants started to blend malt and grain whisky and many of the brands we know today were founded by Johnnie Walker, George Ballantine, James Chivas, William Teacher, Arthur Bell, John Dewer and Matthew Gloag. The sap sucking insect Phylloxera decimated the French cognac trade in the 1880s so a ready export market grew. In 1915, Lloyd George stipulated that whisky should be matured for two years before sale (it increased to three a year later) thus stopping the sale of un-aged product. This put the price up and curbed consumption aimed at preventing drunkenness from harming the war effort. This restriction is still in force today.

So wars, prohibition and economic problems saw unblended single malts fall out of favour with only two malt distilleries remaining in 1933. Grant’s started to promote its Glenfiddich from 1971 and the trade has hardly looked back since with mothballed plants reopening and large new ones being built notably Edrington’s Easter Elchies (Macallan) and Pernod Ricard’s Dalmunach both on Speyside. There are many smaller new builds as well with Lindores Abbey opening again in 2017.

Over 100,000 bottles of rare whiskies were auctioned last year, the only bottle of 1926 Macallan featuring a hand-painted design by Irish artist Michael Dillon fetched £1.2m at Christie’s in London or else you can buy a decent enough 10yo in the supermarket for £25.

We saw how to make the actual malt in the February blog. The distiller wants to get maximum spirit yield, the main barley variety at the moment is Concerto which will yield around 410 litres of pure spirit per tonne. Distillers particularly on the island of Islay make whisky with a distinct smoky aroma. In the old days when peat was the prime kiln fuel, all scotch would have been smoky. Ardbeg, Laphroaig or Lagavulin can be quite a challenging malt and not everybody likes them so peating is generally a lot more constrained. Distillers can specify levels of phenols added during the kilning process to suit their spirit types.

Cooling the condenser water before discharge into the stream at Isle of Arran.

Water is often soft but afforestation can interfere with water run off as trees take up the water trapped in the peat and local agriculture can lead to nitrate run off as well as coliform bacteria from cattle slurry. Water quality needs ongoing careful assessment where carbon filtration and sterilisation may be necessary. Distillers use a lot more water in cooling the spirit either in shell and tube heat exchangers or else the traditional worm tubs where copper pipes snake through a bath of water. Either way there are rules about temperature of the discharge to avoid boiling any passing salmon.

The semi lauter gear at Bladnoch and mashing paddles at Glengoyne.

Malt is crushed and mashed with three successive water batches. The first two go forward for fermentation, the last is recovered and used for the next first mash. The wort in a brewery is called wash in the distillery and it is not boiled. Temperatures gradually increase from 64o, to 78oC to near boiling for the third mash. A deep mash tun runs the wash off slowly, a semi lauter tun with knives but they do not go up and down would take 6.5 hours, a full lauter tun is faster and mash filters as used at the new Inchdairnie plant in Fife gets the wash off fastest. The wash would be cooled to 20o in winter and 17o in summer. The yeast is usually Distillers M strain which is delivered to Scottish distilleries in a milk round from AB Mauri’s plant at Hull. Spent yeast from breweries in England used to be pressed, bagged and shipped northwards but the quality on receipt was patchy. This blogger remembers an empty trailer which had taken fish to Billingsgate calling in at Burton on Trent to collect a load. There were still fish inside and the brewery refused to load it. Next day the local Town Hall was inundated with calls about every waste bin within a quarter of a mile of the brewery being crammed full of fish!

The 44,000L wash backs at Bladnoch – they are only filled to 26,000 to avoid overfoaming.

Wash fermenters can be wood or stainless steel. Wooden ones which are difficult to keep sterile may allow the growth of lactic acid bacteria to contribute to the volatile components which will later be concentrated by distillation. Fermentation temperatures are much higher than when making beer to encourage the formation of these volatile components. The wash would be collected at around 1060o gravity, it has not been boiled as in beer making so that degradation of the malt starch continues in the vessel and the finishing gravity will be around 998o which is some 7.7%ABV. The top temperature might be 34oC but any higher and a lot of alcohol is carried away with the CO2 gas. Some distilleries will fit condensers on the vessel vents to collect it. To prevent frothing over there will be a switching arm which is positioned some 100mm above the wash surface and rotates at 120rpm to break up the foam. If there is a power cut, a bottle of antifoam is kept in reserve! Cotswold adds a spoonful of butter; butterscotch, geddit, has the visitors in stitches apparently!

Fermentation takes up to four days and the wash is then ready to remove the alcohol and those all important volatiles which the distiller calls congeners. We shall consider the different types of still and the distillation process next time.

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