2011 Ferments

[SiSandrine]

Is there such thing as 'food grade' copper sulphate? If I was going to buy some what would I look for. Lots on ebay but unclear whether when it says 'pure' does that mean 100% or shouldn't I be worried.

[NorthernWiner]

"Food grade copper sulphate" is probably an oxymoron since it's not something you would normally want to consume. I would think that pure chemical grade CuSO4 is pure enough. Even if it were slightly adulterated with something else, you are (or should be) only applying it in dosages measured in parts per million.

Incidentally, the residual limit of copper in wine allowed by US law is something along the order of 0.5 ppm, which is a miniscule amount.

Be careful using this stuff.

[SiSandrine]

Thanks Steve. I just wanted something more exact thean the stir with a copper rod as I don't know exactly how much I am adding in that case. I have mild burnt rubber - I think caused by reduction in contact with the lees. I left it slightly too long through the MLF. I did an oxidative racking and this hasn't completely dealt with the issue.

[malcmackenzie]

Grapes

Hi All of you

Being tthe newbie whre are you all getting tthese grapes from?

Dont want to miss out next year do I.

[NorthernWiner]

Thanks Steve. I just wanted something more exact thean the stir with a copper rod as I don't know exactly how much I am adding in that case. I have mild burnt rubber - I think caused by reduction in contact with the lees. I left it slightly too long through the MLF. I did an oxidative racking and this hasn't completely dealt with the issue.

Simon, something to be aware of is that H2S in wine goes through several stages. As it interacts with alcohol, it can eventually evolve into mono-mercaptans, and finally into disulphides. At each stage, it will take on different characteristics and become progressively more difficult to remove. The trick is in determining at which stage the H2S in your wine is presently.

With the rubber smell you describe, it may well be at the mono-mercaptan stage. Copper sulphate is still effective at this stage, but don't allow it to progress any further.

If it has already progressed to the disulphide stage (with characteristics of cooked cabbage), it will be more difficult to remove. At this stage, you would have to first break down the disulphides to mercaptans with an addition of ascorbic acid (vitamin C). Then you can use copper sulphate to treat it further.

I would suggest reading through this page on the British Columbia amateur wine site. It contains a great deal of useful information on dealing with stinkiness caused by H2S.

[Cellar_Rat]

Being tthe newbie whre are you all getting tthese grapes from?

Me !!

[Cellar_Rat]

Simon "I left it slightly too long through the MLF." I don't think is the cause here - what else has happened?

[SiSandrine]

Brian - simply that in order to be sure that MLF had finished I left the wine slightly too long on the gross lees. It is not everywehere and has affected only 2 of the containers from the same batch.
I did think at first it was tainted by the rubber bung from the better bottle. The bung does smell, well rubbery. But taking Steves advice to not wait I have stirred with a copper rod a couple of times (about 10 mins in total) and that seems to have removed the rubber smell. Unfortunately, though I have ordered some copper sulphate, it is not likely to be here until next week.
I will test again later to ensure I am not having olfactory failure.

[SiSandrine]

I would suggest reading through this page on the British Columbia amateur wine site. It contains a great deal of useful information on dealing with stinkiness caused by H2S.

Excellent article thanks Steve.

[Cellar_Rat]

Simon, No saying its not so2. 100% agree with Steve.
It's just that it has happened to a couple of folks now and I for one would like to better understand it.

When you say 'gross leas' - after pressing?

If its not too much trouble...

Which grape?
Which yeast?
1st or 2nd run?
Do you use nutrient ?
Enzymes ?

Grapefest gives us a very unusual opportunity to compare results across different Grapes , ingredients and processes. We can all learn a lot.

[SiSandrine]

Brian, Sure I started to get a bit suspicious too after I saw Koombers post.

Sangiovese
BM4x4
See below extract from my log.

10/09/2011
6 Boxes Sangiovese. Crushed and added packet oak chips, bentonite, Rohapect as per manufacturers instructions.

Sulphited @ approx 5ml / 10%.
Punched down 3 x per day whilst fermenting.

11/09/2011
Morning - evidence that natural fermentation had begun.
PM prepared yeast (BM 4x4) starter.
Quite an earthy smell and taste.

12/09/2011
Added BM4x4 yeast starter - first thing.

13/09/2011
Added a small handful of oak chips.
Added 1 tsp per gallon (if estimated pressed juice) of Tronozymol.
Rigged up heating system to shed to raise temp from 16c to 21/22c
TA for the Sangio was 8.25 g/l as tartaric.
I made up a sugar solution to 1.080 added 11 litres to must, mixed as 60litre container was then very full and decanted some into another bucket.
Idea was to reduce acidity to 6 g/l as tartaric.

15/09/2011
Cap slightly weaker.

16/09/2011
SG 1.016
Earthy smell and taste much reduced.

18/09/2011
Pressed (E & C very helpful).
1 x Better Bottle (free run)
2 x Plastic DJ (free run).
1 x DJ (press)
3/4 DJ (press)

19/09/2011
Racked where very heavy lees deposit.
Added Brouwland MLF - PM.
Moved indoors to 21/22c
SG 996

05/10/2011
Moved to shed (outside) temp consistent at 22/23

17/10/2011
Smell of H2S in Better Bottle and one of plastic DJs (neither of these were racked prior to MLF)
Racked all containers except the 2 press DJs.
Stirred affected with sterilised copper rod - smell reduced.
Added 5ml 10% k-meta per gallon.

[Cellar_Rat]

It will be interesting to compare this with Koombers!

Koomber !!
Koomber !!
Koomber !!

[Cellar_Rat]

Hmm.... Help me understand - did you what a natural fermentation first?


10/09/2011
Rohapect as per manufacturers instructions.
Sulphited @ approx 5ml / 10%.
Punched down 3 x per day whilst fermenting.
11/09/2011
Morning - evidence that natural fermentation had begun.


The Sulphite seems to have made no difference to natural fermentation starting, but was this the source of the H2S later on?

[SiSandrine]

Yes I did want to start with a small amount of natural fermentation. I believe it unlikely that S02 additions would be the source of the H2S from what I have read. I think Koomber had problem with the Merlot.
In order of most likely to least likely I am going with

1. Left too long on gross lees.
2. Late spraying of grapes with sulphur in the vineyard. Put this down to grapes for export and poor European summer.
3. Stressed yeast in fermentation with insufficient nutrient. I added nutrient part way through ferment so again unlikely.
4. I overdid it with heavy toast oak chips - I believe this can cause problems though think it unlikely in this case.
5. Early S02 additions. Very unlikely.

Thinking about this a combination of 1 and 2 would be a distinct possibility.

[goldseal]

I have just checked mine. This might help:

Sangiovese: bm4x4 yeast, H2S detected
Merlot: MT yeast, no H2S
Elderberry/Blackberry, plus sangiovese skins (complete with BM4x4): H2S detected
Sangiovese Rosé: D47 yeast, no H2S

The extent of the problem seems to vary depending on the fermenter: the free-run fermenters have a hint, but the ones containing pressed must stink.

I hope that helps. Time to deploy the copper pipe (again )


EDIT: forgot to mention: none were racked before ML innoculation.