2011 Ferments

[NorthernWiner]

Don't be discouraged too quickly. It may take time for all of these different elements to interact before you notice an improvement. I added CuSO4 to a stinky Riesling last Saturday. It still stunk immediately afterward. Today, though, it smells fresh and clean.

[goldseal]

Thanks for the encouragement Steve .

I noticed the smell did fade in the test glass (Ascorbic + CuSO4) after a couple of hours, but I wonder if that was just because it was open to the air. It faded in the control glass too, but not as much.

I'm tempted to add Ascorbic, then a 'reasonable' dose of CuSO4 and see what happens. It is trashed anyway if I leave it, so what is the worst that can happen?

[lockwood1956]

I'm tempted to add Ascorbic, then a 'reasonable' dose of CuSO4 and see what happens.

What could possibly go wrong?

[koomber]

Nooooooooo........


Seriously Pete, I wouldn't (yet). For starters you might induce a copper haze (from steve's link) also if you put too much Copper sulfate it and it doesn't crash out you might have a poisonous batch of wine...

Looking at the link from steve:

http://www.bcawa.ca/winemaking/h2s.htm

The key thing is:
Ascorbic acid in conjunction with copper sulphate works very well, but it is not instantaneous; it takes several days before the odour and taste disappear. Do not exceed the recommended dosage of copper sulphate or you may induce a copper haze which will be difficult to remove.

If I could make a suggestion (working from what the link has said).

1. Take two samples of wine.
2. Treat with 25ppm of ascorbic acid (Add and stir)
3. One sample will be left for one day(sample 1), the other two days (sample 2).
4. When your sample is ready take a sniff and compare to the original wine. Has the smell changed at all? Any differences in smell could be an indication of disulfides.
5. Treat this sample using the copper sulfate solution. Treat slowly to determine the amount required. If there is no effect, wait a day (or two!) and test again on the second sample.

I'll postface that advice by saying that I don't know exactly how you've carried out your test, but this should at least allow you to better gauge the performance before going all 'Scottish diet' on it (ie. completely mental).

Also, it's been a bit chill at night maybe the colder temps are having an effect?

[goldseal]

Thanks Graham. Oddly enough, I had the same sort of thought which awoke me at 3am .

That doc you mentioned is the basis of my testing. The tests suggest adding ascorbic, waint a few minutes, then adding CuSO4, and checking the smell straight away. However the instructions for treatment are to add Ascorbic, wait a day, then add CuSO4. As you said, not instantaneous.

My 3am plan was to do more or less as you suggested - treat, seal up, wait, test. I think your plan makes perfect sense.

Cheers for the advice (I like your Reason for Editing )

[Cellar_Rat]

Last edited by koomber; 08-11-2011 at 09:30 PM. Reason: THIS MESSAGE IS BROUGHT TO YOU BY THE 'PEOPLE CONCERNED THAT THEY WONT GET TO SNAFFLE PETE'S BEERS AT GF 2012' PARTY

LOL. Very good.

[robwrx]

I'm relieved to say that my stinky Trebbiano has responded well to the stirring with a copper rod and both affected djs now smell and taste fine.

I did notice the lack of acid which Koomber confirmed a while back so I have increased the TA of one dj to 6.5g/lit to see if it improves the taste.

[goldseal]

H2S / mercaptan / disulphide test (Koomber's method) (sort of).

100ml samples in 3 bottles:

1. untreated stinky Sangiovese
2. treated with 5 drops 10g/l ascorbic acid on Day 1, 5 drops CuSO4 (0.41g/l) on Day 2
3. treated with 5 drops 10g/l ascorbic acid on Day 1, and nothing else yet

Bottle 2 immediately BEFORE adding CuSO4: definite reduction in smell. Still not 'nice', but definitely less eggy/farmyard.

Day 3:
Bottle 1 still smells

Bottle 2 (ascorbic + CuSO4) vs Bottle 3 (ascorbic only): Bottle 2 smells cleaner to me. However, I may just be smelling a metallic (coppery) tang .

Frustratingly, the only thing which would really clinch it would be a taste test. Presumably not recommended!

Because the change can apparently take days or even a couple of weeks, I intend leaving them for a few more days and having another sniff.

Opinions?

[koomber]

H2S / mercaptan / disulphide test (Koomber's method) (sort of).

100ml samples in 3 bottles:

1. untreated stinky Sangiovese
2. treated with 5 drops 10g/l ascorbic acid on Day 1, 5 drops CuSO4 (0.41g/l) on Day 2
3. treated with 5 drops 10g/l ascorbic acid on Day 1, and nothing else yet

Bottle 2 immediately BEFORE adding CuSO4: definite reduction in smell. Still not 'nice', but definitely less eggy/farmyard.

Day 3:
Bottle 1 still smells

Bottle 2 (ascorbic + CuSO4) vs Bottle 3 (ascorbic only): Bottle 2 smells cleaner to me. However, I may just be smelling a metallic (coppery) tang .

Frustratingly, the only thing which would really clinch it would be a taste test. Presumably not recommended!

Because the change can apparently take days or even a couple of weeks, I intend leaving them for a few more days and having another sniff.

Opinions?

Seems to be going quite well. The fact that the smell has changed from the addition of the ascorbic acid is a fairly clear indicator that you've reacted out with the ascorbic. The copper sulfate seems to be going for it pretty well too.

[goldseal]

True, but I'm not sure that I trust my sense of smell - I really don't want to end up poisoning somebody

[Rich]

True, but I'm not sure that I trust my sense of smell - I really don't want to end up poisoning somebody

That's never stopped you before..

here and here and here

Mainly just alcohol poisoning with that, rather than added metal.

Good times though..

[koomber]

A fair point!

Steve used a 1% solution in a 5 gallon batch. it's about 30 drops of 1% in 22 litres. Translating this means that he used about 1.36 drops of 1% copper sulfate per litre.

You used 5 drops of 0.41g/L in 100mL. Let's convert the g/L into % and your looking at 0.04% coppersulfate. At your dose your using 50 drops of 0.04% coppers sulfate per litre.

Or putting it another way:

50 drops of 0.04% coppers sulfate

Which is the same as

5 drops of 0.4% coppers sulfate

Which is the same as

0.5 drops of 4% coppers sulfate

Which is the same as

2 drops of 1% coppers sulfate per litre.

Not a million miles from Steve's quantites

Also the copper sulfate will precipitate out when it reacts with the H2S. Thus, if you leave it for a day to settle out and then rack off leaving some wine in the bottom then you should help lower the copper levels in the wine. At this point you are just wanting to check the taste is gone so just go for a splash in the mouth followed by spitting and rinsing. You should now know if it worked.

PS: Ascorbic acid = vitamin C which is why I've not bothered with it.


ANOTHER BOOMING EDIT

I've just had a thought! We can safely assume that Steve's loadings were safe to work with, but if you are concerned about the 2 drops Vs. 1.36, you could always dilute the wine with some water before tasting. Your only really looking for the swamp taste, so you should be okay.

[goldseal]

Thanks for the reassurance, Graham. I'll let you know how I get on (or Mrs. G will, depending on the outcome ).

Richa - any poisoning there would have been purely self-inflicted

[NorthernWiner]

...We can safely assume that Steve's loadings were safe to work with, but if you are concerned about the 2 drops Vs. 1.36, you could always dilute the wine with some water before tasting.

It should also be noted that here in the U.S., it's allowable to add up to 6.0 ppm of copper to wine for the treatment of H2S, provided that only 0.5 ppm or less remains in the finished wine. This is an important distinction.

If you feel that your wine has too much copper, a bentonite fining will remove almost all traces of it quickly. Granted, we probably only want to fine as a last resort, but know that it is an option. Just leaving it alone for a period of time will also allow it to dissipate. Copper, being a metal, will eventually sink to the bottom of your storage vessel.

One other thing on this subject. Copper is present in our diet in a number of mineral-rich foods. According to the US Environmental Protection Agency, it would not be a stretch to consume up to 10 milligrams of copper on any given day simply by eating a lot of potatoes or chocolate.

As with anything else in winemaking, just use a modicum of caution, and try not to sweat the details too much.

[SiSandrine]

Just tasted my Sangiovese for the first time since November. Delighted with it. Smoothing out a treat lovely flavour, light fruity redcurrant with slight marzipan tones and just a touch of vanilla. Twill be a very nice wine indeed in a year or so.