Re: Cab Franc H2S - 3+ Weeks Old!

Zinman,
Thanks for the information. It is my understanding that gross lees are the
resultant lees from pressing; I did not leave the must lying around for 3
weeks. The caps were punched down 3x per day but no nutrients added.

If you're saying leaving the wine in contact with the lees from pressing for
three weeks is poor practice, I am surprised as I've done it over 4 weeks
last year for all my wines and the other 6 varieties this year do not
exhibit any odors.

I do not believe I've gotten to mercaptan so I am still confident the wine
will come back.

If not, I wonder if the vinegarmakers can advise whether wine afflicted with
H2S can become a safe, decent vinegar!


    Patrick


"zinman" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> "Patrick McDonald" <[EMAIL PROTECTED]> wrote in
message news:<[EMAIL PROTECTED]>...
> > I racked off the gross lees 3 weeks after pressing.  I've not added, or
> > intend to add, an ML culture but to let nature take it's course. I added
0.5
> > tsp. sulfite to the 72 lbm. of must before inoculation.
> >
> > I've added the copper (I poured into a funnel which I fitted with a
copper
> > pipe outlet about 16 inches long) and then stirred today with the same
> > copper tubing but still believe I have some H2S left. We'll see over the
> > next day or two. Perhaps the copper fitted to the funnel did not aerate
> > enough.
> >
> > The initial odor was.. WOAH - big. Hopefully I can rein this in.
> >
>
>  Patrick
>
>  Sounds like your problem is very serious. Most yeast produce a small
> amount of H2S during fermentation, a whiff of rotten egg. Low
> nutrients in the grape must also stress the yeast and produce the
> odour. Punching down the cap often and yeast nutients deal with that.
> Usually aeration after fermentation till the stink is gone followed by
> sulfite additions cure the problem. However, leaving the wine on the
> heavy grape solids...GROSS LEES... for three weeks could be and is
> terminal as the gross lees reduce (rot). There comes a point where
> hydrogen sulfide will chemically change to another compound called
> mercaptan. This has a distinct "skunk" aroma and once it has settled
> into your wine there is no treatment for the home winemaker. It is
> used in propane and natural gas to alert people to gas leaks. If your
> wine smells like that dump it and be the wiser next year. If it just
> smells of rotten egg vigorous racking with metallic cooper(pipe) or
> "Cufex" may help. Careful with cooper as small amounts are toxic.
> There is a product called "Bockskin" that bonds to the H2S and removes
> the stink. Forget about ML fermentation if any of these techniques
> work as you will need to add more SO2 than the bacteria can survive.
>                                                   Sorry For The Bad
> News