Every so often we run across someone who is trying to make wine using bread yeast or baker's yeast. Yes, I'm talking about the plain ole' yeast you pick up in the baking aisle of your local grocery store. And every time I hear of someone using this yeast, the question that always screams at me is, "why?"
There are so many advantages to using wine yeast and so many disadvantages to using bread yeast that I can't imagine why anyone would want to use it. The only conclusion I can come up with is that there is a strong misunderstanding about what yeast really are and what they do.
Yeast are what turn sugar into alcohol. They are living organisms that consume and digest the sugars. As a result, they excrete alcohol and CO2 gas. Along with these two compounds also come various trace amounts of enzymes, oils, acid, etc. These are the things that give different alcohols their different characters.
The thing to understand here is that all yeast are not the same. How one strain responds to the sugars varies from the next. There are literally thousands of different strains that have been identified or developed as hybrids, all with varying characteristics that make them suitable or not-so-suitable for performing a particular task.
This brings us back to the bread yeast. Most bread yeast will ferment alcohol up to about 8% with ease, but when trying to produce alcohol beyond this level, the bread yeast begin to struggle, very often stopping around 9% or 10%. This is short of what we'd like to obtain for almost any wine.
Bread yeast do not clear out very readily or settle very firmly, either. They typically will form a low layer of hazy wine in the bottom of the fermenter that will never completely clear out.
Even more importantly, bread yeast produce alcohol that is plagued with a lot of off-flavors. The bread yeast have to work so hard to produce the alcohol that off-flavored enzymes and fatty acids are produced along with the alcohol.
There are several other issues with using bread yeast, but these are the big ones: the alcohol, the clearing, and the flavor.
There are many, many different strains of wine yeast. These yeasts are bred over time to produce something of a 'super' wine yeast. Each one becoming the ultimate choice for tackling the particular task at hand.
Some ferment to total dryness better than others. Some have better alcohol tolerance than others. Some put off fruitier aromas than others. Some pack more firmly to the bottom of the fermenter than others. Some wine yeast even have flavor qualities that make them ideal for fermenting one type of fruit over another. The list goes on and on. And it goes without say, they do it all better than bread yeast.
On our website, we have a wine yeast profile charts listed for each line of wine yeast we carry: Red Star, Lalvin and Vintner's Harvest Wine Yeast. You can view these profile charts from a link on the product page for each of these wine yeasts.
The last thing I'd like to point out is that buying actual wine yeast is not that expensive. Currently, you can purchase wine yeast for as little as $1.55. I haven't priced bread yeast recently, but there can't be that much difference in price. So if you value your time and effort at all go with the wine yeast not bread yeast.
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.