Why do we need to add yeast?

[klutz]

I just saw a video about a place in France where they make wine. They said the yeast is in the skin. Why do we still need to add yeast?

Another question I have is: Why are table grapes not considered good for wine making?

 

[Arne]

A lot of fruits will take off and ferment on their own. When you add the winemaking yeast you use a strain that should ferment all the sugars and not add any unwanted flavors. I'll let somebody else answer your other question. Arne.

 

[dralarms]

Table grapes are high in sugar but low in flavor. I've tried it, you get rocket fuel. No flavor.

 

[cmason1957]

If you were to go to a winery and taste a wine grape alongside a table grape, you would know why they use the grapes they use. Wine grapes are much higher in sugar, almost candy sweet and have a much different bite to them than eating grapes. As in they have much higher acidity to them.

 

[richmke]

I just saw a video about a place in France where they make wine. They said the yeast is in the skin. Why do we still need to add yeast?

Do a search on yeast, and there are a bunch available. Each yeast has its own flavor profile. I am sure that the place in France has natural yeast that it is happy with. Not necessarily true if you are starting your own winery in a new area.

You could make the same argument about water. Water is virtually free out of the tap. Why should I pay for bottled water? If you local water (natural yeast) is good, then don't bother. But, if you water tastes horrible, then you might want to pay for bottled water.

 

[DoctorCAD]

There is a big difference between natural yeast and local dominant yeast. In that specific area of France, the winemakers hvav probably used a specific strain of yeast for hundreds of years. It has become the local dominate yeast. Natural yeast are probably still there, but get beat out by the wanted yeast. If grapes from a different area were used, they might not have the same dominate yeast and their natural yeasts might make a different flavor wine.

Consistancy is the big issue in wine.

 

[GreginND]

Agree with what the good Doctor said.

 

[seth8530]

Yup, you pitch yeast for consistent results or to achieve a desired fermentation profile since different yeast have different affects on the wine.

 

[klutz]

There is a big difference between natural yeast and local dominant yeast. In that specific area of France, the winemakers hvav probably used a specific strain of yeast for hundreds of years. It has become the local dominate yeast. Natural yeast are probably still there, but get beat out by the wanted yeast. If grapes from a different area were used, they might not have the same dominate yeast and their natural yeasts might make a different flavor wine.

Consistancy is the big issue in wine.

Yes, they did say that each place had its own special taste. They also said that each wine is different, according to the personality of the wine maker. That must have meant according to each wine maker's taste, I guess.
What do you mean that the natural yeast "get beat out by the wanted yeast" ?

 

[klutz]

Do a search on yeast, and there are a bunch available. Each yeast has its own flavor profile. I am sure that the place in France has natural yeast that it is happy with. Not necessarily true if you are starting your own winery in a new area.

You could make the same argument about water. Water is virtually free out of the tap. Why should I pay for bottled water? If you local water (natural yeast) is good, then don't bother. But, if you water tastes horrible, then you might want to pay for bottled water.

Thanks, that makes sense. I think I will search it. Hopefully, it won't be too complicated.

 

[klutz]

If you were to go to a winery and taste a wine grape alongside a table grape, you would know why they use the grapes they use. Wine grapes are much higher in sugar, almost candy sweet and have a much different bite to them than eating grapes. As in they have much higher acidity to them.

Do you mean that a wine grape should be very sweet and very acid? I noticed the skin is tougher too, or is that just a sign of not-so-good wine grapes?

 

[GreginND]

First: most of the yeast we use is natural. The wine yeasts have just been isolated and propagated from their natural sources, most from France. There are very very few engineered yeasts.

There are thousands of natural yeast strains. When the Doctor is talking about "natural yeasts being beat out" he is talking about the fact that most of the yeast strains found all around us are weaker than the ones that have been isolated and used for making wine. The stronger strains that we add to the must take over and outcompete for nutrients. They become the dominant yeast in the fermentation. The weaker strains are also knocked down with sulfites that we add prior to fermentation.

 

[DoctorCAD]

Yes, they did say that each place had its own special taste. They also said that each wine is different, according to the personality of the wine maker. That must have meant according to each wine maker's taste, I guess.
What do you mean that the natural yeast "get beat out by the wanted yeast" ?

Say you lived in Tuscon and stuck a bunch of fruit in a bucket. The natural yeast would start fermenting but if you added a specific wine yeast with a specific flavor profile, that yeast has been bred to overwhelm natural yeasts and would beat out the natural yeast. The natural yeasts will die from sugar starvation.

 

[richmke]

The esteemed Ken Wright of Ken Wright cellars described what he heard at the meeting as “Amazing”, and went on to note that the findings “flew in the face of what I and most people were assuming happens in fermentations…Wild fermentations are anything but wild. Yes, you have a strain that is identified as wild. But that strain is almost immediately overwhelmed by house yeast. Within the first few days of fermentation, they are gone. The commercial strains fight it out for domination.”
http://fermentationwineblog.com/2013/08/wild-yeast-fermentation-theres-no-such-thing/

The question is: Is the Commercial Strain that wins the one you want?

 

[klutz]

The question is: Is the Commercial Strain that wins the one you want?

Did any of you try not adding yeast, and if you did, what did it taste like?

 

[petey_c]

I just saw a video about a place in France where they make wine. They said the yeast is in the skin. Why do we still need to add yeast?

This is very similar to some Belgian beers. They use wild yeasts to ferment the brew. These beers are usually sour tasting. That trait, although usually undesirable is most other beers, is necessary for Belgian sour beers (Flemish Red, Lambic, etc.). I'm not a big sour fan. I guess it's an acquired taste.