A new yeast being marketed internationally is based on research by WSU food scientist Charlie Edwards and colleagues. The aim was to develop a product that can stand up to mature grapes to achieve the robust wines today’s consumers prefer.
Ideally, yeast should perform consistently batch after batch, regularly metabolizing a certain amount of sugar into ethanol. Today’s winemakers are encouraging growers to leave their grapes on the vine longer to increase the sugar content — producing bigger, bolder wines. So today’s yeasts must be able to handle the extra sugar.
Increased sugars can stress a wimpy yeast, resulting in a sluggish or “stuck” fermentation — an expensive, stinky disaster for a commercial winery and a disheartening mess for a home winemaker. Or, a yeast may gobble up as much sugar as it can in the first few days of fermentation, resulting in wine with more hydrogen sulfide and giving the finished product a rotten-egg smell.
Partnering with commercial yeast producer Lallemand, Edwards formulated strains that can stand up to high-sugar grape musts (unfermented juice). Lallemand is marketing the yeast internationally, and each package bears text saying “developed in collaboration with Washington State University.”
Although the precise formulation of Lallemand’s yeasts is a trade secret, Edwards said the difference is in the process of manufacture.
“We looked carefully at a large number of products under commercial winemaking conditions” before zeroing in on strains that performed consistently and had a nutritional profile suitable for the flavorful wines so esteemed by today’s consumers, he said.