Why yeast
 

My father of italian origin has been making perfect wine for years and
has not once used yeast. What is the purpose of adding yeast? What
does it do?

Richard Sulfaro

Why yeast
 

In article >, (Richard Sydney) wrote:
>My father of italian origin has been making perfect wine for years and
>has not once used yeast. What is the purpose of adding yeast? What
>does it do?
>
It turns sugar into alcohol. And it's *impossible* to make wine without it.

Your father is getting yeast from somewhere. Not necessarily buying it from a
winemaking supply outlet, mind you: he may be depending on wild yeast (which
are literally everywhere), he may be starting fermentation of each batch with
yeast from the lees of the previous batch, or even fermenting his wines in a
wooden barrel that's become impregnated with yeast over the years -- but he's
using some kind of yeast from somewhere.

Why yeast
 

There will always be some yeast spores...of some kind...on the grapes.
Introducing a cultured wine yeast gives you a better chance of
obtaining a pleasant and predictable wine....the wild spores may make
great wine, but may just as often not make good wine.


Truenorth

On 8 Apr 2004 22:46:25 -0700, (Richard
Sydney) wrote:

>My father of italian origin has been making perfect wine for years and
>has not once used yeast. What is the purpose of adding yeast? What
>does it do?
>
>Richard Sulfaro

Why yeast
 

Hello,
I am also Italian and most of my relatives still do NOT add any yeast to
their crushed grapes. There will always be wild yeast present in all fruits.
The crushed grapes always start fermenting on their own. The wine will be
noticeably better with the addition of store bought yeast. I assume that the
wild yeast will still grow and reproduce along with the cultured yeast. You
may want to add campden tablets to the crushed grapes to kill off any wild
yeast spores present before adding cultured yeast just to be sure.
Most wine made by leaving the crushed grapes alone produce good results.
However, most of the problems arise from improper cleanliness and oxidation,
turning a good wine bad rather quickly. The old school vintners are hard to
change in their methods :-) My father used to use an old oak barrel to
ferment his grapes in. The old (15 years++) wood harbored many a bacteria
and usually produced bad wine. It took years of convincing to switch to a
plastic fermented that was sterilized!!

Al
"Richard Sydney" > wrote in message
om...
> My father of italian origin has been making perfect wine for years and
> has not once used yeast. What is the purpose of adding yeast? What
> does it do?
>
> Richard Sulfaro

Why yeast
 

> <snip> the wild spores may make
> great wine, but may just as often not make good wine.

Saying it that way seems to imply that wild spores will
make great wine and a packet of yeast will make somewhat
less great wine. In fact most of the purchased yeasts are
cultured exactly because they create great wine. IMO, you
probably have a chance at creating as great wine with
wild spores as you do with cultured yeast but doubtfully
better and almost assuredly worse. Unless the area the
grapes came from is "ripe" with a great natural yeast and
then it's still a crap shoot.

Don

Why yeast
 

Wine grapes ( grapes period), make there own yeast for fermentation,,,,,com.
yeast only speeds up the process and costs you more....Grampa is
right....Such is experience in your trade ....donny
"Richard Sydney" > wrote in message
om...
> My father of italian origin has been making perfect wine for years and
> has not once used yeast. What is the purpose of adding yeast? What
> does it do?
>
> Richard Sulfaro

Why yeast
 

"donny" > wrote in message
...
> Wine grapes ( grapes period), make there own yeast for
fermentation,,,,,com.
> yeast only speeds up the process and costs you more....Grampa is
> right....Such is experience in your trade ....

That's inaccurate. Grapes do not "make" yeast. The waxy white coating on
the grape skin (called the bloom) causes airborne yeasts to adhere to the
grapes. When the grapes are crushed the yeasts come in contact with the
juice, which renders them active, resulting in fermentation.

If you're lucky, the fruit will have "caught" a friendly strain of yeast and
the wine will turn out OK. If not there may be a serious problem with
excess production of volatile acidity by competing spoilage organisms.

Sounds like grampa has been lucky.

Tom S

Why yeast
 

"donny" > wrote in message >...
> Wine grapes ( grapes period), make there own yeast for fermentation,,,,,com.
> yeast only speeds up the process and costs you more....Grampa is
> right....Such is experience in your trade ....donny
> "Richard Sydney" > wrote in message
> om...
> > My father of italian origin has been making perfect wine for years and
> > has not once used yeast. What is the purpose of adding yeast? What
> > does it do?
> >
> > Richard Sulfaro

There is so much I disagree with in this, I don't know where to start.

1) Grapes do not "make" yeast. There may be wild yeasts present on the
grapes, but it may not give the characteristics you're looking for.

2) Speed is not the only reason cultured yeast is used for
fermentations. Certain yeast strains are used to promote specific
characteristics in the finshed wine. It also reduces the chance of
stuck fermentations. Some yeast strains consume more malic acid than
others. The list goes on and on why cultered yeasts are used.

3) Cost. $1 for a packet of yeast is a small price to pay for piece of
mind.

Yes, there are commercial wineries that do not add yeast. Most of
these have been around for a long time and the vineyard and winery
have a dominant strain all over the place. This strain works for them
to create the style of wine the want.

There are also many commercial wineries, even in "the old world", that
use cultured yeast to insure the strain they want is the dominant one
in the fermentation.

In home wine making, relying on wild yeast is a crap shoot.

Andy

Why yeast
 

A lot depends on where the grapes come from. If the grapes are from an area
where grapes have been grown and wine has been made in the vineyard for many
years, then probably a good wine quality yeast is the dominant yeast growing
on the grapes. If the grapes are from an area new to growing grapes or
where few grapes are grown the other wild yeasts are probably the dominant
yeast growing on the grapes. Adding a good strain of yeast to the must is
just insurance. Insurance is purchased, or not, at the discretion of the
individual. Some people are luckier than others.

Ray

"Richard Sydney" > wrote in message
om...
> My father of italian origin has been making perfect wine for years and
> has not once used yeast. What is the purpose of adding yeast? What
> does it do?
>
> Richard Sulfaro
>

Why yeast
 

One issue that has not been brought up is "YEAST FINNING" (All Reds).
This is a technique used to increase the amount of phenolics donated
to the wine
fom yeast. Commercial yeast or wild yeast may be used for the primary
fermentation, but active yeasts are added to the wine after dryness to
increase mouthfeel and reduce bitter and astringent flavors. When the
active and rehydrated yeasts are added they will produce polyphenols
as the lyse and eventually fall out of the mixture to settle at the
bottom of the tanks. The wine should be left on these dead yeasts
until maturity is obtained. This "fining" should take place after an
appropriate aging period.
Note: Be careful to monitor any VA as the yeast will become a nutrient
source for any opportunistic spoilage yeasts or bacteria. One of the
most predominant American wild yeasts Kloeckera Apiculata also has
high VA levels, so I also recoment that primary fermentations use
comercial, low VA yeasts with proper nutrition.
A good strain for yeast fining is Lalvin D254

> >

Why yeast
 

I would have thought the the reason for using commercially produced
yeast over naturally produced yeasts is that the results are more
controlled and the alcohol produced of as know type (i.e. ethonol).
Certain types of alcohol are toxic to humans and I believe these types
can be produced by using wild yeasts (In some circumstances).

Allowing wild yeasts to be used in your ferments can produce
unpredictable results leading to stuck ferments, off tastes and
Volitile Acidity problems.

I know of many people who only rely on wild yeasts to ferment however
I have never had the bottle to experiment and waste a once a year
opportunity by taking a chance.

Lets face it, many older italian winemakers produce superb wine one
year and average the next. Isnt it all about being consistent year
after year...?

AB1



(Zack S) wrote in message . com>...
> One issue that has not been brought up is "YEAST FINNING" (All Reds).
> This is a technique used to increase the amount of phenolics donated
> to the wine
> fom yeast. Commercial yeast or wild yeast may be used for the primary
> fermentation, but active yeasts are added to the wine after dryness to
> increase mouthfeel and reduce bitter and astringent flavors. When the
> active and rehydrated yeasts are added they will produce polyphenols
> as the lyse and eventually fall out of the mixture to settle at the
> bottom of the tanks. The wine should be left on these dead yeasts
> until maturity is obtained. This "fining" should take place after an
> appropriate aging period.
> Note: Be careful to monitor any VA as the yeast will become a nutrient
> source for any opportunistic spoilage yeasts or bacteria. One of the
> most predominant American wild yeasts Kloeckera Apiculata also has
> high VA levels, so I also recoment that primary fermentations use
> comercial, low VA yeasts with proper nutrition.
> A good strain for yeast fining is Lalvin D254
>
> > >