Wine making yeast is an essential ingredient for any kind of wine, whether you are making wine for a large estate that produces commercial wine (which of course you would only do if you were suitably trained) or making your own wine at home. For this reason it is essential to choose good-quality yeast that will do the job.
So what exactly is the job that yeast has to do?
In two short words, it makes alcohol . And it is alcohol that makes the difference between wine and ordinary grape juice.
Yeast and wine making
To make wine, we need to combine grapes (in some form or other) with sugar, water and yeast – sometimes with the addition of other ingredients. The sugar and yeast react and that's when fermentation starts to take place, and the whole mix begins to look like a frothy witch's brew. It's quite a strange process because it also makes the sugar less sweet. That is why any type of wine, sweet, semi-sweet, dry or extra-dry (brut) needs sugar to make it. On average, you are going to need about 2 lbs of sugar for every gallon of wine you produce – and that will end up with a wine that has an alcohol content of around 10 percent.
If you look around for yeast you will quickly see that there are different types of yeast for different applications. Even though most come from one particular species, Saccharomyces cerevisiae , manufacturers use the same species to make yeast for brewing beer, making whiskey, bread and for other purposes as well. Just be warned that you can't use yeast produced for making bread, beer or anything else to make wine!
So it isn't just a matter of going to your local supermarket and asking for "yeast". It really does need to be the right type, and it also need to be a decent quality. If it isn't, then you have no chance of producing a good, drinkable house wine. You might as well go a bottle of the shelf.
Dry versus wet
Most people tend to use dried yeast for wine making, but you can also use liquid yeast. It does the same job but more quickly, and many people will say a lot more efficiently.
If you buy a wine making kit you will usually get dry yeast. That isn't a train smash. All you will need to do is to activate the yeast yourself in warm water before you add it to the water, sugar and grape mix.
If you are serious (or get serious) about making wine, then you will soon find which type of wine yeast works best for you.