Getting creative with yeast
December 6, 2016
by Laurie Gorton
Instant active dry yeast now comes in lean-dough and sugar-tolerant styles.
Bakers give yeast a big assignment: Leaven our goods. While mixing creates air cells within bread doughs, it’s the gases released by bakers yeast as it ferments that expand those cells to produce the desired light, airy texture in the finished product. Leave the leavening out, and the results will be tough, hard and barely edible.
Saccharomyces cerevisiae, a.k.a. bakers yeast, packs a lot of power into a microscopic single-celled plant, a fungus actually. In nature, yeast exists as millions of different strains, each with varying properties. Every yeast manufacturer maintains a library of well-characterized proprietary strains, propagating commercial batches from the purified cultures. Each batch from a given culture will be identical in properties. This production method ensures that the bakers yeast you select will work the same every time you use it.
Unlike flour, yeast optimized for bakery performance is a relatively new development. In 1868, the first standardized commercial yeast, Fleischmann’s Yeast (now part of AB Mauri North America’s portfolio), was introduced to the US by an Austrian brewer, Charles Fleischmann, and his brother Maximilian.
The diversity of yeast allowed individual processors to move beyond fresh yeast into compressed and bulk formats and to later add the cream yeast style. It helped them find the right strains to stand up to the rigors of drying while still remaining active.
“The majority of commercial bakers prefer conventional fresh yeast,” said Ralf Tschenscher, baking business development manager, Red Star, Lesaffre Yeast Corp. But that hasn’t limited creativity.
Recently, suppliers have tapped the organism’s gene pool to provide properties that fit specific bakery needs. These include tolerating high sugar levels, standing up to freezing or fighting formation of acrylamides. Some offer vitamin fortification, while others were developed to fit the stringent code of organic certification.
In the end, it’s all S. cerevisiae. The different forms lend flexibility to bakery production, and the different strains add functionality to formulating choices.
Changes in categories
The organic market is one of the trendiest food sectors in the world. Its double-digit growth rate, currently pegged at 11.4% annually in the US, exceeds all other categories of the food industry, according to the Organic Trade Association. It accounts for $43.3 billion in total organic product sales, with bread and grains a solid No. 3 in category size after fruits/vegetables and dairy.
The National Organic Program of the US Department of Agriculture (USDA) strictly regulates the ingredients used in certified-organic foods through the National List of Allowed and Prohibited Substances. The rule for yeast states that organic yeast must be used when labeling foods as organic, unless it is not commercially available. Until lately, it had not been. It is now.
At the 2016 International Baking Industry Exposition, Red Star, a unit of Lesaffre Yeast Corp., introduced organic bakers yeast, certified to USDA standards. “We were getting so many requests for a certified-organic bakers yeast,” Mr. Tschenscher said. “USDA organic certification also includes the sourcing of the substrates and nutrients.”
The organic style is produced on a dedicated line. Mr. Tschenscher noted that Red Star is currently working on certified-organic instant active dry (IADY) bakers yeast. The company also has capacity on a dedicated line to make certified-organic inactive yeast.
Two years ago, Lallemand introduced organic yeast in fresh, compressed style under the company’s Wieniger Bio and Malteserkors brands and in dry format as part of the Instaferm family.
“It’s unique in the manner of its manufacture,” said Gary Edwards, president, Lallemand North American Baking. “It must be grown with certified-organic substrates and nutrients. For example, we can’t use ammonia as the nitrogen source vital to yeast’s growth. We have to go to other organic sources of nitrogen. The same is true for the vitamins and other nutrients required. Also, we are limited on which cleaning chemicals can be used.”
A semi-dry yeast remains frozen during mixing and makeup, thus adding months to the shelf life of frozen doughs.
Instant dry yeast (IDY) was developed to give bakers more convenience in use, particularly for straight doughs that allow little or no floor or fermentation time. Unlike active dry yeast, which much be hydrated before use, IDY goes right into mixer with all the other dry ingredients. No soaking, brews or liquid ferments are needed. And as its popularity increased, so has its variety.
“We offer a range of IDY products because different baked goods have different requirements,” said Walt Postelwait, president, Pak Group North America. The company supplies two types. Its Red product is for lean doughs. Its Gold strain is naturally sugar-tolerant and intended for doughs containing 6% or more sugar.
The first IDY products made by other suppliers often contained ascorbic acid, a dough strengthener. To match those products, Pak Group added ascorbic acid to its Red and Gold styles. “But some bakers don’t want this additive,” Mr. Postelwait explained. “So we developed our Green and Blue versions. Green is based on our Red lean-dough yeast while Blue is the equivalent of our Gold sugar-tolerant yeast.”
Frozen dough poses a distinctive problem for yeast. Although makers of frozen dough products try to keep mixing and makeup time as short as possible to minimize yeast activation, some will start fermenting. The baker would often double up on yeast in the formulation, but even so, most yeast will die off in 60 to 90 days, Mr. Postelwait explained.
Pak Group produces Semi-Dry Yeast by a proprietary method. IDY typically goes dormant during its vacuum packaging step. The company’s semi-dry process adds a freezing step that puts the yeast to sleep. Used in frozen dough, the semi-dry yeast stays dormant during the mixing, processing and freezing stages. “This gives a much longer shelf life to the frozen dough; nine to 12 months are typical,” Mr. Postelwait said. “You also only need to use the normal amount of yeast, instead of having to double up.”
Lallemand recently introduced a proof-tolerant yeast, FlexFerm. Available in fresh or dry format, this yeast takes advantage of a strain of S. cerevisiae that does not ferment the maltose in flour. Thus, the amount of leavening gases it produces is controlled by the quantity of sugar added to the formula.
Proofing stops when the added sugar is depleted, according to the company. “At present, this technology performs optimally for lean doughs with low sugar,” the company stated.