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01 January 2006
Malting at Port Ellen
By
Brad Richards
It was after an impromptu visit to Port Ellen Maltings that I decided to write this article. We called at the Maltings unannounced, only to find that we had hit their silent season, three weeks where the Maltings are shut down to allow for maintenance work. Despite this, we were treated to a warm reception by the manager, John Thomson, who is a fountainhead of knowledge.
Whisky is made from just three ingredients; barley, water and yeast; and then there is a secret but often critical influence, peat. It is at the maltings that these ingredients first come together. Most distilleries buy their malt from central malting plants, like Port Ellen. This is not only for cost reasons, the floor maltings found at Bowmore, Laphroaig and a handful of other distilleries, are terribly labour-intensive . but also for reasons of quality. Consistency in malting is very important for the final product, both consistency from batch to batch and, even more importantly, amongst the grains of a single batch. The milling and mashing at a distillery can be adjusted to account for differences between batches of malt, but inconsistencies within a batch lead inevitably to lower yields and may well affect the final whisky. However romantic floor maltings may be, they produce far more uneven results than drum maltings such as those at Port Ellen.
But before the malting process can even begin, the ingredients must be to hand, and the most important of these is barley. There are many varieties of barley, useful for different things: flour, beer, grain whisky, and of course malt whisky. Of prime importance is the starch content: more starch produces more alcohol. Different varieties of barley do produce slightly different flavour components, but these differences are overwhelmed by subsequent differences in distillation and maturation.
Once the barley has been selected, it must be germinated. Germination releases the enzymes that will later break the grain's stored starch into bite-sized pieces for the yeast. It also breaks down internal structures in the grain so that the starch is more accessible.
To germinate, the barley needs water and oxygen, and again consistency is critical: all barley grains must germinate at the same rate, meaning the supply of water and oxygen must be uniform.
At Port Ellen, the barley is wet in great steep tanks. After soaking for several hours, with hourly stirrings, the water is drained away and air is blown through the grain to provide oxygen. This process is repeated a total of three times, until the grain has absorbed nearly its own weight in water, at about 45% moisture, the grain is ready to go into the malting drum.
The making drums at Port Ellen are enormous, the largest in the UK, and very possibly in all of Europe. The grain rests on a perforated floor, and the sides of the drum have spiral fins that, when the drum rotates , serve to stir and spread the grain evenly on the floor. Temperature and humidity are carefully controlled, and in about five days, germination has reached the desired point: the enzymes have been released and cell walls have been broken down, but the embryonic barley plant has not yet broken into the store of energy contained in the large starch particles within the grain.
The external indications are clear: rootlets have emerged from the base of the grain, and a shoot has started to grow underneath the husk, from the base of the grain toward the tip.
The next step is drying the grain to halt the germination process. Drying is done in large kilns . the grain is again spread evenly on a perforated floor, and air, at 55C to 70C, is blown through it from underneath. This is the point where the secret influence comes in to play. Peat gives whisky a particular flavour due to compounds known as phenols. Phenols are released in the smoke as peat heats towards burning temperature. A good peat fire has a hot core that heats the outer layers to produce clouds of smoke. As the outer layers begin to burn in earnest, more peat must be added on top. If the fire burns too hot, it can be slowed by adding water.
Some years ago, Port Ellen Maltings attempted to make the peating process more scientific: pulverizing the peat, steam-injecting exactly the right moisture content, pressing it into pellets, and heating the pellets to exactly the right temperature to release the phenols. This intensive and expensive process improved matters not at all, so now it's back to traditional peat fires.
The fires provide the smoke, but most of the actual drying heat comes from oil-fired burners. Smoke components adhere best when the grain is still damp, so peat is only used at the start of the kilning. Different distilleries require different amounts of peat in their malt, from none at all to upwards of 50ppm of phenols. A moderately peated malt (well, moderate for Islay) requires about 100kg of peat for every tonne of malt, double this amount is required for very heavily peating. That tonne of malt will in the end, produce over 400 litres of whisky.
Once the barley has been dried to around 5% moisture content, it is called 'fiery malt'. For reasons not entirely understood, fiery malt is not very good for producing whisky, it mills poory, clogs mash tuans, and produces less alcohol than it ought. All these problems are easily solved: the malt is stored for a few weeks, and is then ready for use.
One last process is carried out before malt is stored: the rootlets put out during germination are removed by vibrating the malt on a screen. These, along with barley dust generated during malting, are processed into cattle feed. At Port Ellen, this presents an unique problem: Port Ellen Maltings produces malt for all of the Islay distilleries, so this is highly peated cattle feed. Islay cattle don't mind at all (smoked beef, anyone?), but during the summer the feed is sent to the mainland . where the cattle don't appreciate it at all. Perhaps they would prefer a lighter Speyside?"
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