Whisky Magazine Issue 85
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Ian Wisniewski asks: What is lactobacillus, and what influence can this have during the production process?
A little known fact about whisky production is that every distillery has its own population of different types of bacteria, with lactobacillus being the key group that affects the production. This happens during fermentation when lactobacillus produces lactic acid (another name for this group is also known as lactic acid bacteria), as well as acetic acid, which help to promote the level of esters (fruity notes) in new make spirit.
First, what are the factors which determine the level and range of bacterial presence in a distillery?
There are a number of elements determining the levels of bacterial presence in a distillery including the environment within the distillery's washbacks, whether they are wooden or stainless steel; the levels of hygiene and cleaning regimes and mash tuns, as well as the length of fermentation.
Meanwhile, malted barley is where it all begins.
“Malted barley has a mix of microbes on its surface when it arrives at the distillery, including various species of lactobacilli and wild yeast.
“That source of bacteria can be influenced by various factors, including harvest conditions,” says Dennis Watson of Chivas Bros technical and scientific director.
The next stage, milling, doesn't affect bacteria, but mashing certainly does. During mashing the grist (ie milled barley) and its accompanying bacteria are subjected to three (or even four) waters at progressively higher temperatures culminating at 85-90 degrees centigrade.
“Some lactic acid bac...