[Seagram logo.]
[View of field with large tree.]
There's something out here, which holds the key to the secret of good whisky. Yeast, grows successful fermentation. We all know about the yeast that makes bread rise, that puts bubbles in the beer.
[View of grass and flowers.]
But there are also wild yeasts all about us in the grass, in the air, in the flowers. Thousands of different strains! [Researchers gather plants containing yeast.] To find yeasts with efficient fermentation characteristics and a unique flavour contribution, Seagram went back to the source. Researchers gathered thousands of samples of wild native yeasts travelling the country from east to west. The wild yeasts found in the pollen of these flowers were a long way from a usable pure culture. [External view of distillery.] They would be taken back to the distillery where the long process of selection incubation and purification would single out the best. [View of yeast culture in a petri-dish and in several test tubes.] From the thousands of specimens, five, after years of testing prove to be of a quality and character suitable for fermentation of Seagram whisky. [View of vacuum-tubes containing freeze-dried yeast being sealed.] Samples of these precious yeasts are freeze dried and kept in suspended animation in vacuum-tubes, one of the most closely guarded secrets of an industry. When yeast is required for fermentation one of these tiny vials is broken open and the dried cells brought back to life in a nutrient solution. Here they will thrive and grow under the right conditions. Yeast reproduces rapidly and will soon use up a flask of sugar medium. It grows by ingesting sugar, in this case the maltose or sucrose molecules in the converted grain mash.
[Schematic of active yeast culture.] Here we see how the yeast cell takes in the maltose molecule through its permeable cell walls. Enzymes in the yeast break down the sugars allowing the cell to grow and divide. When all the molecules have been used up the flask is full of yeast cells. This in turn is added to a larger tank of grain mash called the doughnut tub. Here the yeast will work for twelve or fourteen hours until it has grown to sufficient volume to inoculate a whole fermenter. In the fermenting room the vast tubs of cooked grain mash are waiting and the yeast wastes no time as the vigorous bubbling testifies.
[Schematic of yeast consuming sugar molecules and producing congeners and alcohol.] Under the surface there is equally hectic activity. The grain mash contains millions of sugar molecules, all of which must eventually be consumed by the yeast cells. The distiller's interest in this is two-fold. Firstly, flavouring elements, called congeners, will be created as the yeast enzymes break down the molecules - important to the flavour of the future whisky. And then of course, there is the production of alcohol created by the fermentation process, along with carbon dioxide gas - all that busy bubbling in the fermenter. After three to five days the bubbling will cease, this means the yeast has done its job and is no longer active. Where there were maltose molecules before now there is an eight-percent alcohol solution, known in the industry as distiller's beer. Its destination: the Stillhouse, where the fermented mash will be distilled into a pure crystal clear spirit. The third stage in the making of a Canadian whisky. [External view of the Stillhouse.]