Technique

Yeast Nutrient Strategies

Grape juice is a pretty tough environment if you’re a yeast cell. The pH is low, there’s high osmotic stress (stress from the environmental conditions being such that the flow of water out of the cell is favored), and often, essential nutrients are limited. The abundance of fermentable sugars, however, makes life in these challenging surroundings worthwhile for our single-celled eukaryotic friends. Our charge as winemakers is to try and ease some of this stress so the yeast can efficiently convert the sugars to ethanol, and hopefully produce some delicious aroma compounds along the way. One way to alleviate yeast stress is by providing proper nutrients. This article will shed some light on why yeast need nutrients and what they do once they have them. I hope this knowledge will help when making decisions about what nutrients to add and when to add them in the winemaking process. Before we get too far along, let’s review classes of nutrients required by yeasts for efficient fermentation, so we can talk about each one in more detail below. Nitrogen – Yeast require