Yeast is a very important part of the wine making process. It is used to turn the sugars that are in fruit, into alcohol. With out it, people would just be making juice. Some wine makers even like to let their wines age on the yeast to modify the flavor of their wine into a product that has a slight bread taste to it. Generally, wine makers will want to filter this out of their wine right away and dispose of it.
Did you know that once yeast has served its purpose as a wine creator is is not just garbage afterwards? It can have several purposes that include animal feed, diet supplements and tartaric acid creation.
Spent yeast can be used for animal feed after it has been processed. This is because it contains protein, carbohydrates and vitamins, all of which are important to any living creature. There is actually a demand for wine processing waste and can be considered as another source of income for wine producers.
Some companies have found uses for wine waste by turning it into dietary supplements for humans. This is because spent yeast has a substance in it called beta glucans. Beta glucans are extracted from the yeast through the use of chemicals or boiled in water.
Tartaric acid is another part of spent yeast that can be valuable. Tartrates are used in the preservation of food and they also have many anti oxidant properties.
If you are a gardener you might want to consider just using the spent lees as compost. They will benefit your garden because they are full of nutrients. Maybe you could even put it around your grape vines to improve next years harvest.
Another thing that I have heard is that some beer brewers put it back in the boiler to use as a yeast nutrient for the next batch of yeast that will be happily working away.
This is why, when you look at that gross sludge in the bottom of your fermenting bucket you should not be so quick to throw it away. There are many uses for spent yeast and possibly more if you can think up some of your own ideas.