Yeast is essential for fermentation, the critical process that converts grape juice into wine. Although most grapes have enough natural yeast on their skins to start a reaction, relying only on spontaneous fermentation is risky (though some producers do exactly that). What if there isn\u2019t enough yeast to finish? What if it takes too long, or it leaves sugar that can be consumed by bacteria that cause spoilage?\r\n\r\nWinemakers unwilling to shoulder those perils typically add pure yeast cultures to their fermenters. This makes fermentations more reliable and helps deliver more consistent wine sensory profiles.\r\n\r\n\r\n\r\nThese cultures come from a yeast cultivator, whose job\u2014as it sounds\u2014is to propagate, grow and manage pure yeast. These companies either dry yeast cultures or bottle them fresh and sell them to winemakers, brewers, sak\u00e9 makers, kombucha enthusiasts and more. The job is part science, part art and all important to the industry.\r\n\r\nGetting the right yeast is critical because these microbes are more than just the engines of fermentation. Different yeasts produce different outcomes.\r\n\r\n\r\n\r\n\u201cWith bread, you\u2019re looking for yeast to produce gas to make the bread rise,\u201d says Didier Theodore, new business development and yeast product manager for Lallemand Brewing, which has produced yeast cultures since the 1970s. Theodore works alongside Anthony Silvano, yeast product manager at Lallemand Brewing in oenology. \u201cFor wine, you are looking for yeast to consume sugar and produce alcohol and aroma. It\u2019s completely different," says Theodore.\r\n\r\nGiven that aroma matters at least as much to wine as flavor, finding the right yeast is vital and tricky. A yeast strain that produces ideal results with one grape variety will not necessarily work as well with others.\r\n\r\n\r\n\r\n\u201cFor Sauvignon Blanc, you want to ferment it to preserve the fresh aromas,\u201d says Theodore. Someone who makes Chardonnay, on the other hand, may want to emphasize creamy or yeasty flavors.\r\n\r\n\u201cWe will test the yeast in different conditions in the lab,\u201d he says. \u201cThen, after fermentation, we will taste the wine and make some analyses of the wine to see which kind of aromas have been produced during fermentation.\u201d\r\n\r\nIn addition to identify and capture strains that will offer something new or different, yeast cultivators also work closely with beverage producers to help solve problems.\r\n\r\n\r\n\r\n\u201cWe serve as a source of technical information for the fermentation industry,\u201d says Dr. Matthew Winans, a research and development scientist at Imperial Yeast, founded in 2014. \u201cWe do that by working with customers to troubleshoot problems they\u2019re having and leveraging lab resources to solve problems.\u201d\r\n\r\nWhether it\u2019s a tried-and-true yeast or a new one, cultivation typically starts in the lab with a single yeast cell. \u201cWe isolate it, propagate it, and it grows,\u201d says Winans. \u201cOnce the lab achieves growth to a sizable quantity, we move it over to the production facility.\u201d\r\n\r\nThe job is part science, part art and all important to the industry.\r\n\r\nThe production team inoculates the yeast into a sterile slurry called bulk media, which is where the yeast grows. The yeasts reproduce until there\u2019s a sizable quantity to sell.\r\n\r\nFor technicians in both the lab and production, much of the job is to monitor the yeast cultures to ensure they\u2019re healthy and pure, and to clean the facility so that bad microorganisms don\u2019t contaminate the final products, says Winans.\r\n\r\n\r\n\r\nAt Imperial Yeast, the team uses a thermal cycler that monitors real-time polymerase chain reactions by detecting fluorescence in samples and allowing lab techs to copy DNA from yeast in the bulk media and test it to see if it has contaminants. A fluorescence-imaging machine allows them to count cell density from an image to package consistent concentrations of yeast cells.\r\n\r\nOne of Theodore\u2019s favorite parts of the job is working in the field.\r\n\r\n\u201cIt\u2019s fun because the brewing industry and the wine industry are very social,\u201d he says. \u201cThey\u2019re an international element to the work because we are selling our products all over the world. We are also making a product to make people happy.\u201d\r\n\r\nWorking for a yeast cultivator isn\u2019t all about discovery and drinking, though. There\u2019s some bias toward the profession, especially in Europe.\r\n\r\n\r\n\r\n\u201cWhen you start to speak about yeast, people think that you are putting something strange into the grape juice, and this is not something that\u2019s natural,\u201d says Theodore. It\u2019s challenging to explain to people that you\u2019re taking the best from nature and using it to craft a natural product.\r\n\r\nThere are other unglamorous aspects to the career. Anyone who interacts with the yeast must clean or sanitize workspaces and equipment, and that\u2019s not for everyone, Winans says . The job also requires a person who is highly organized, has great attention to detail, can communicate well with other team members and is very thorough.\r\n\r\nSomeone who appreciates this type of work but doesn\u2019t have an advanced degree in microbiology can still have a good career in yeast cultivation. \u201cAn interest in microbiology and fermentation helps,\u201d says Winans. \u201cWe can teach or train just about any employee on anything they want to know, but we can only do that if someone has a desire to learn and an interest in this field.\u201d Flexibility, an ability to work with a team and a willingness to put in long days when necessary are other qualities he looks for.\r\n\r\n\r\n\r\nTo work in R&D or more advanced positions in a lab, \u201cyou need to have a good knowledge of microbiology and different microorganisms\u2014which are good, which are bad,\u201d says Theodore.\r\n\r\nPeople who can rise to the occasion and work in yeast cultivation will find it an interesting, fulfilling career.