During this time, using a new cooling technique developed by Carl von Linde, Heineken gained the ability to brew year round at a consistent quality level. Heineken was thus one of the first breweries in the world to eliminate the brewer's traditional dependence on seasonal natural ice. In 1879 Heineken hired Dr. Elion, a former student of Louis Pasteur, to research yeast. Over the next 13 years Elion systematically bred and selected a specific yeast cell for Heineken, which came to be known as the 'Heineken A-yeast' (yeast being the source of alcohol and carbon dioxide in beer). The Heineken A-yeast would continue in use into the 21st century and would eventually be shipped from Holland to all breweries owned or operated by the company, providing for a uniformity in taste among Heineken products, regardless of the different climates in which they were produced or consumed.
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