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By the time breweries take on multiple strains in the brewery towards widening their portfolio of beer styles an extra level of complication arises in management of these pure cultures. If the beer recipe in question is truly a one-off product such as a seasonal beer the brewery must either order a pitchable amount of a liquid culture or go through the process of propagation of a pure culture within the brewery. If ordering pitchable amounts from a supplier typical lead times can be lengthy. In-house propagation of a culture from a yeast slant can shorten that time to within 3 to 5 days from start of propagation in the lab. In both situations brewery operations need to synchronise to the availability of the yeast. Live liquid yeast cultures require food and nutrition. While keeping a propagated or cropped slurry under cold conditions for a day or two will most likely still yield good performance in fermentation the truth of the matter is that when yeast is deprived of what it needs to live its metabolic activity changes towards adjusting to such an environment. By the time a liquid culture that has been stored for days is added to wort to begin fermentation it can be expected that the fermentation performance will be compromised to varying extents depending on the storage conditions and on the nature of the individual strain. Testing...1 2 3 Regardless of whether the liquid yeast slurry is fresh from the brewery propagator straight out of a bottle from a yeast supplier or directly transferred from the bottom of a vessel at the end of fermentation testing for percentage of viable cells and calculating yeast pitch is critical for consistent results in finished beer. Brewers want to get through fermentation and beer finishing in the most timely fashion possible and yeast health is critical to achieve that end. However yeast health also plays a key role in many aspects of the characteristics of finished beer especially in flavour and aroma. Fermentation products like diacetyl sulfur and a range of esters are dependent on consistent yeast performance so pitching an accurate quantity of cells with a known level of viability is critical with every batch. Yeast counts are not that difficult to conduct but still many breweries lack the lab equipment or trained manpower to perform the tests on a regular basis. Many brewers rely on established practice of pitching a consistent amount of litres of slurry into each batch which could be compromised to the detriment of product quality. The cost of lost production of beer in raw materials energy and time is too high to be allowed. The Dry Yeast Advantage With the worldwide growth of interest in craft beer and brewing comes both opportunity and challenge. To stay relevant in the eyes of beer consumers brewers need to embrace creativity and innovation by expanding the diversity of their products or risk losing customers to their competition. The creation of exciting beer styles depends in many respects on using the right yeast and fermentation techniques to meet the criteria of the style of beer being brewed. While managing multiple strains of liquid yeast in a brewery presents challenges there is an option that simplifies the process of expanding a brewerys beer style range. That option is the use of dry brewing yeast. As little as 10 years ago there were limited strains of dry brewing yeast available. Today brewers can choose from a wide selection of pure brewing strains in dry form that allows them to create a huge range of beer styles both traditional and New World. During production dry yeast starts its life as a liquid culture and the moisture from the yeast is carefully removed in a way that results in a remarkably stable product that offers excellent performance in brewing. Vacuum-packed dry yeast can be stored in refrigerated conditions for as much as 2 years with little change it its fermentation performance. This means that brewers not longer need to schedule wort production to synchronise with availability of a liquid yeast culture but rather active dry yeast can be kept on hand at the brewery and used whenever it is required. Each batch of dry yeast has been tested in every aspect of performance and purity assessing viability vitality and even its genetic profile. This ensures that brewers have a consistent standard of performance with each yeast batch. Importantly brewers dont need to calculate viability and measure liquid volumes of yeast slurry. Instead dry yeast is simply measured by weight making calculation of the pitched amount of active cells both accurate and easy. Dry yeast is rehydrated in a couple of simple steps just before it is to be used for pitching and the liquid slurry is then added to wort in the fermenter to initiate fermentation. Fearless Brewing Managing multiple yeast strains towards creating an amazing range of beer styles doesnt need to be complicated given the selection and ease-of-use of dry brewing yeast. Brewers can fearlessly experiment with creation of exciting new brands knowing that they can count on the reliable performance and consistency provided by dry yeast in whatever recipes they choose. 63 Keith Lemcke is Vice-President at Siebel Institute of Technology which has been in the brewing yeast business since 1872 providing a full range of yeast banking and maintenance services to some of the greatest names in brewing. that is yeast 63_Layout 1 21042016 1522 Page 1