Mold on harvested grapes - ???

Mold on harvested grapes - ???

Post by Alexander Miller » Mon, 28 Sep 1998 04:00:00



Harvested abt 1/4 of my grapes leaving the rest on vine to ripen more.
Put the picked ones in a covered, unrefrigerated plastic primary
meantime. Now after several days they show a white mold growing where
the skins are broken. Am I right to think I can still use them for
wine, and how can I be sure? Thanks for all advice. (Email appreciated
as I know some posts don't show up here.)

Alexander Miller, Port Alberni B.C. Canada

 
 
 

Mold on harvested grapes - ???

Post by Peter H. Jord » Mon, 28 Sep 1998 04:00:00


Alexander, Miller. schrieb:

Quote:
> Harvested abt 1/4 of my grapes leaving the rest on vine to ripen more.
> Put the picked ones in a covered, unrefrigerated plastic primary
> meantime. Now after several days they show a white mold growing where
> the skins are broken. Am I right to think I can still use them for
> wine, and how can I be sure? Thanks for all advice. (Email appreciated
> as I know some posts don't show up here.)

First advivice : throw them away.

Second advice : if you do not want to throw them awy, than press the
grapes and taste the juice. If the juice has a slightly rotten smell, than
use one to two gram powdered   charcoal per 10 litres to fine the must.
But the first advice is the better one.

--
    Peter H. Jordan      Weingut JORDAN & JORDAN
      (Winemaker)

--- Life is too short to drink bad wine ---

Der Saarwein : "http://www.saarwein.com"
Wein Forum   : "http://www.saarwein.com/cgi-bin/Ultimate.cgi"

 
 
 

Mold on harvested grapes - ???

Post by Giovan » Wed, 30 Sep 1998 04:00:00


Quote:

>says...

>Harvested abt 1/4 of my grapes leaving the rest on vine to ripen more.
>Put the picked ones in a covered, unrefrigerated plastic primary
>meantime.

Double mistake. I am sure you realize by now. Next time, sulfite and
store at low temperature (the lower the better).

Quote:
>Now after several days they show a white mold growing where
>the skins are broken. Am I right to think I can still use them for
>wine,

Yes. Depending on quantity, you may be able to wash off most of the
mold (immersing in water and lightly shaking, jet-spraying with your
water hose, etc..). Then I suggest sulfiting at 150-200 ppm (it's not
as bad as it sounds!) and let rest tightly covered in cool room (10-14
is OK) for 48 hours.

I also suggest you prepare a yeast starter for a 'fast start'.

Quote:
>and how can I be sure?

No guarantees. But the odds are pretty good! Chances are you will not
have any problems whatsoever. What have you got to lose? Someone else
may advise to get rid of them. I suggest you go ahead.

Quote:
>Thanks for all advice. (Email appreciated
>as I know some posts don't show up here.)

>Alexander Miller, Port Alberni B.C. Canada


Best of luck,    Giovanni.
 
 
 

Mold on harvested grapes - ???

Post by Alexander Mille » Wed, 30 Sep 1998 04:00:00


Giovanni,

HI & thanks for the repsonse to my post about mold on grapes. Guess I
should pay attention to grape advice from anybody called Giovanni  : )

Sadly I think the grapes have pre-empted all your suggestions as
there's now a spontaneous ferment underway. I think I'll just let it
go and see what I have once it's finished. They are concord grapes so
it's not as if I might lose some "premium" juice. If it doesn't taste
noxious near the end I can add sugar syrup, or more grape juice, and
carry on.

I"ve only ever made "country" wines before; sometimes using grapes but
always in low quantity, with lots of sugar to raise the SG, so I don't
understand, if molds are undesirable, how do "real" winemakers (i.e.
using just grapes) avoid them without sterilising the fruit and
thereby killing off the natural yeasts? How do they avoid what I've
ended up with?

I don't suppose I'm going to poison myself - what d'you think? (I
won't hold you responsible if you're wrong - come back & haunt you or
anything!)

Alexander Miller, Port Alberni B.C. Canada

Quote:

>Harvested abt 1/4 of my grapes....
> Now they show a white mold growing.....
>still use them for wine, how can I be sure?

And got the reply:
Quote:
>>.....Next time, sulfite and
>>store at low temperature (the lower the better).
>>Depending on quantity, you may be able to wash off most of the
>>mold (immersing in water and lightly shaking, jet-spraying with your
>>water hose, etc..). Then I suggest sulfiting at 150-200 ppm (it's not
>>as bad as it sounds!) and let rest tightly covered in cool room (10-14
>>is OK) for 48 hours.
>>I also suggest you prepare a yeast starter for a 'fast start'.
>>No guarantees. But the odds are pretty good! Chances are you will not
>>have any problems whatsoever. What have you got to lose? Someone else
>>may advise to get rid of them. I suggest you go ahead.
>>Best of luck,    Giovanni.

 
 
 

Mold on harvested grapes - ???

Post by Chad T. Johnso » Wed, 30 Sep 1998 04:00:00


Alexander,
Most commonly , winemakers will crush grapes as soon after picking as
possible and will
add metabisulphite to inhibit wild yeasts and ohter organisms( though not
all will use metabisulfite as some really are against chemicals in their
wine). After the meta has had a chance to do it's thing, cultured yeast is
added to out - muscle the competition. In your
case I would add some wine yeast to it if u think there is any chance it
will turn out o.k.
A book on winemaking can be very informative or you could look at this
groups FAQ
Good Luck, Chad
Quote:

> Giovanni,

> HI & thanks for the repsonse to my post about mold on grapes. Guess I
> should pay attention to grape advice from anybody called Giovanni  : )

> Sadly I think the grapes have pre-empted all your suggestions as
> there's now a spontaneous ferment underway. I think I'll just let it
> go and see what I have once it's finished. They are concord grapes so
> it's not as if I might lose some "premium" juice. If it doesn't taste
> noxious near the end I can add sugar syrup, or more grape juice, and
> carry on.

> I"ve only ever made "country" wines before; sometimes using grapes but
> always in low quantity, with lots of sugar to raise the SG, so I don't
> understand, if molds are undesirable, how do "real" winemakers (i.e.
> using just grapes) avoid them without sterilising the fruit and
> thereby killing off the natural yeasts? How do they avoid what I've
> ended up with?

> I don't suppose I'm going to poison myself - what d'you think? (I
> won't hold you responsible if you're wrong - come back & haunt you or
> anything!)

> Alexander Miller, Port Alberni B.C. Canada


> >Harvested abt 1/4 of my grapes....
> > Now they show a white mold growing.....
> >still use them for wine, how can I be sure?

> And got the reply:

> >>.....Next time, sulfite and
> >>store at low temperature (the lower the better).

> >>Depending on quantity, you may be able to wash off most of the
> >>mold (immersing in water and lightly shaking, jet-spraying with your
> >>water hose, etc..). Then I suggest sulfiting at 150-200 ppm (it's not
> >>as bad as it sounds!) and let rest tightly covered in cool room (10-14
> >>is OK) for 48 hours.

> >>I also suggest you prepare a yeast starter for a 'fast start'.

> >>No guarantees. But the odds are pretty good! Chances are you will not
> >>have any problems whatsoever. What have you got to lose? Someone else
> >>may advise to get rid of them. I suggest you go ahead.

> >>Best of luck,    Giovanni.

 
 
 

Mold on harvested grapes - ???

Post by Bryan Caspe » Wed, 30 Sep 1998 04:00:00


Quote:

> Sadly I think the grapes have pre-empted all your suggestions as
> there's now a spontaneous ferment underway. I think I'll just let it
> go and see what I have once it's finished. They are concord grapes so
> it's not as if I might lose some "premium" juice. If it doesn't taste
> noxious near the end I can add sugar syrup, or more grape juice, and
> carry on.

> I"ve only ever made "country" wines before; sometimes using grapes but
> always in low quantity, with lots of sugar to raise the SG, so I don't
> understand, if molds are undesirable, how do "real" winemakers (i.e.
> using just grapes) avoid them without sterilising the fruit and
> thereby killing off the natural yeasts? How do they avoid what I've
> ended up with?

Unless these grapes are totally smelling bad or something, why not give them
a dose of sulfites.  Say about 100 - 200 PPM.  Then in a few days,
innoculate with a good quality wine yeast.  Why let the grapes go bad?

In answer to your question,  the guys that do the "natural thing", have a
lot more control than you think.  It's a romantic notion to think that their
wine magically turns out OK.  These people are highly trained wine makers.
The wine yeast which innoculates their grapes runs rampent in their wine
making facility while the bad ones do not.    This does not happen by
chance.

Also you have to keep in mind that wine yeasts will survive sulfites and
will continue living happy, healthy lives long after wild yeast and bacteria
are stunned to submission.  That's why wine makers use sulfites.  Give the
chemical a chance and save your batch of concord wine.  Follow Giovanni's
suggestions.

Bryan Casper

 
 
 

Mold on harvested grapes - ???

Post by DOUG EVAN » Wed, 30 Sep 1998 04:00:00


Quote:
>understand, if molds are undesirable, how do "real" winemakers (i.e.
>using just grapes) avoid them without sterilising the fruit and
>thereby killing off the natural yeasts? How do they avoid what I've
>ended up with?

Ehh,ahhh, I use sulfite to kill all the wild yeast's and ***'s, then go
spend fifty cents on good yeast.  wild yeast's are not very dependable on
what type of off flavor they will contribute.  I've tasted a few wines done
"Au Natural" and in the best intrest of everyone they ought to be dumped
down the terlot.
 
 
 

Mold on harvested grapes - ???

Post by Mr. Fred A. Droe » Thu, 01 Oct 1998 04:00:00


Another suggestion:  If you decide to use the partially moldy grapes,
prepare the starter for a fast start as Giovanni suggests AND ferment
these grapes completely separate from the clean grapes you are picking
later.  See how the wine turns out before mixing the two.  No use
turning a spoiled small batch into a spoiled large batch.
Fred
 
 
 

Mold on harvested grapes - ???

Post by Baccu » Fri, 16 Oct 1998 04:00:00


Oh ok I'll put my 2cents in.

I have worked for a few years with wild yeast; isolated and cultivated them
up from the vineyard where they occur naturally, fermented them off and
isolated the good ferments. Gee , you say...developing yeast cultures?- why
go to so much trouble? Well it's what the 'real' wine makers used to do
before you could buy the 'commercially purified' yeast for 50 cents.And it
is still practised commercially now. It's a bit more trouble but allot of
fun, easy to do after a few trials, and has produced excellent consistent
results. By the way ....in the cool climate area I am from, I have never
once had a stuck ferment with 'wild' yeast...can not say the same for the
'purified commercial yeasts '. Ofcourse some are better than others.

The wines (mostly reds) produced from ferrule ferments' tend to develop more
complexity and are certainly different.They appear to age better in trial
too....but I am not 100% convinced of that yet (have to wait a few more
years)

Oh and I do use commercially available yeast for certain wines I produce
also.

I don't recommend it for everyone, but if you want to try something a little
different give it a go.

Information on cultivating yeast  is available in any good wine making
publication

Regards

Bacuss

Quote:

>>understand, if molds are undesirable, how do "real" winemakers (i.e.
>>using just grapes) avoid them without sterilising the fruit and
>>thereby killing off the natural yeasts? How do they avoid what I've
>>ended up with?

>Ehh,ahhh, I use sulfite to kill all the wild yeast's and ***'s, then go
>spend fifty cents on good yeast.  wild yeast's are not very dependable on
>what type of off flavor they will contribute.  I've tasted a few wines done
>"Au Natural" and in the best intrest of everyone they ought to be dumped
>down the terlot.