Ask the Wine Making Expert – Harm Woldring


Over the centuries the art and science of making wine has progressed however, no matter how much people learn and develop the basic fact is, yeast is the magic ingredient that makes all beverage alcohol possible. There are thousands of varieties of yeast in the world. Some are ideal for bread making, some for beer, others for wines and different varieties are used to create the stock from which distilled spirits are made.

When it comes to wine yeasts for consumer made wines certain important issues need to be considered. Unlike commercial wineries that operate state-of-the-art facilities with micro-degree temperature control and other sophisticated equipment and diagnostic tools, craft wine makers tend to have more rudimentary fermentation and maturation processes. While there may be thousands of yeasts for commercial wineries to choose from, craft wine makers need yeast strains that are far more forgiving in terms of the climate they live in. For example, many yeasts are highly intolerant of temperature fluctuations. Others are sensitive to the volume of alcohol present, and some produce higher levels of Sulphur compounds than others. These are all important considerations and ultimately make the difference between success and failure.

The essential thing to know is that all yeasts consume sugar and produce certain ‘waste’ products, alcohol, carbon dioxide and an array of trace chemical compounds including potassium metabisulphite a common food preservative. A critically important trait of the yeast being used to make beverage alcohol is its tolerance for the alcohol it produces. As the level of alcohol in a must or wort, the word used to describe a liquids undergoing fermentation, rises the yeast becomes less and less efficient. While this is true, at the same time the number of yeast cells in the must increase exponentially as the cells mature and divide. Eventually however, a maximum tolerance level is achieved. In craft wine making it is important to use yeasts that can tolerate a wide range of changeable temperature conditions and that have high alcohol tolerance levels, particularly when making dry wines. Choosing a yeast that delivers a certain flavor profile may be desirable but if its alcohol tolerance level is below the potential alcohol dictated by the amount of sugar present, the yeast will die off before the sugars are completely consumed and a sweet or off-dry wine will result. In the craft wine making industry the extreme range and variety of conditions that the wine could be made in dictates that a limited selection of yeast types are suitable to provide good results across the broad range of conditions.

The study and development of wine, and other, yeasts is a sophisticated specialty area. Both commercial businesses and research labs in universities around the world are focused on developing new yeast strains for all kinds of industries. One of the factors influencing wine yeasts in particular is related to changes in agricultural practices in vineyards. Modern agricultural practices and vineyard design has had a dramatic impact on the fruit produced and harvested to make wine. Increased yields with higher sugar content in the grapes means many ‘modern’ wineries are producing wines with much higher alcohol content. As a result newer strains of yeast with higher alcohol tolerances have been developed. Other yeasts are ‘designed’ to create unique flavors in specific wines. Other areas of research are driven by the need to reduce the levels of Sulphur compounds in wines.

In the end, the craft winemaker and our industry are beneficiaries of all these developments in agriculture and yeast. Our juice suppliers are owned and operated by the world’s and Canada’s largest beverage alcohol companies. As the developments occur within the overall wine industry we benefit with access to an ever broader selection of high quality juices, paired with appropriate yeasts.

The Wine Factory has been serving our clients in and around New Westminster for 21 years. Our current location, in an 19th century building constructed from stone and brick is an ideal environment in which to make wine. We invite you to come down and check us out. If you are looking for a way to make wine part of your daily lifestyle then you should consider becoming a craft wine maker, either with us or, if you are so inclined on your own., 604.540.8907.