Copper Sulphate dosing method

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Handy Andy

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I need a little help with some simple math.

I have a small barrel with 50litres of wine and a lingering feint rotten egg smell, after it had been splash racked twice and left for a couple of weeks.
I read that the addition of copper sulphate up to a maximum of 0.5ppm or 0.5mg/litre can be used to remove hydrogen sulphide smells.
I thought I would do some tests at a dosing level of 0.1ppm and work my way up to 0.5ppm dose to see what worked.

I ordered CuSO4.5H2O copper sulphate crystals. Then I realized my kitchen scales will not weigh anything less than 1 gram.

How much CuSO4.5H2O do I need to dissolve in water to produce a solution that can be dropped into my wine at a sensible rate.

My dropper is 0.05mL or 20 drops to a 1mL

If I take 5g of CuSO4.5H2O (teaspoon) and mix with 500ml of water gives 10g/litre or 10000ppm solution of CuSO4.5H2O and water.

Am I correct in thinking???? > adding 0.1mL, 2drops of 10000ppm solution to 1 litre of wine is equivalent to dosing at 1ppm??? or is it 0.1ppm

Thanks in advance

Edit

Thinking about this overnight. I think ive worked it out.

1gram dissolved in 1litre gives me a solution of 1000ppm approx.
1mL (20 drops) of this solution dissolved in 1 litre of wine gives 1ppm which is too high maybe even toxic.
1mL of solution dissolved in 10litres of wine gives 0.1ppm
1mL of solution dissolved in 50 litres of wine gives 0.02ppm

So >
2 drops of solution, in 1litre of wine gives 0.1ppm
20 drops of solution in 10 litres of wine gives 0.1ppm
100 drops of solution in 50 litres of wine gives 0.1ppm

Or >
taking 100mL glass and adding 1 drop gives 0.5ppm max allowed level.

Sounds right to me,
 
Last edited:

stickman

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Your numbers are off a little due to copper sulfate being only 25% copper by weight.
A 1% copper sulfate solution can be made adding 1g copper sulfate and topping up to 100ml with water.
A .1ppm copper addition would be approximately .15ml of the 1% solution added per gallon of wine.
A .5ppm copper addition would be approximately .75ml of the 1% solution added per gallon of wine.

Use the smallest dose needed to eliminate the odor. Bench trials are recommended to determine the required dose.
 

Handy Andy

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I need a little help with some simple math.

I have a small barrel with 50litres of wine and a lingering feint rotten egg smell, after it had been splash racked twice and left for a couple of weeks.
I read that the addition of copper sulphate up to a maximum of 0.5ppm or 0.5mg/litre can be used to remove hydrogen sulphide smells.
I thought I would do some tests at a dosing level of 0.1ppm and work my way up to 0.5ppm dose to see what worked.

I ordered CuSO4.5H2O copper sulphate crystals. Then I realized my kitchen scales will not weigh anything less than 1 gram.

How much CuSO4.5H2O do I need to dissolve in water to produce a solution that can be dropped into my wine at a sensible rate.

My dropper is 0.05mL or 20 drops to a 1mL

If I take 5g of CuSO4.5H2O (teaspoon) and mix with 500ml of water gives 10g/litre or 10000ppm solution of CuSO4.5H2O and water.

Am I correct in thinking???? > adding 0.1mL, 2drops of 10000ppm solution to 1 litre of wine is equivalent to dosing at 1ppm??? or is it 0.1ppm

Thanks in advance

Edit

Thinking about this overnight. I think ive worked it out.

1gram dissolved in 1litre gives me a solution of 1000ppm approx.
1mL (20 drops) of this solution dissolved in 1 litre of wine gives 1ppm which is too high maybe even toxic.
1mL of solution dissolved in 10litres of wine gives 0.1ppm
1mL of solution dissolved in 50 litres of wine gives 0.02ppm

So >
2 drops of solution, in 1litre of wine gives 0.1ppm
20 drops of solution in 10 litres of wine gives 0.1ppm
100 drops of solution in 50 litres of wine gives 0.1ppm

Or >
taking 100mL glass and adding 1 drop gives 0.5ppm max allowed level.

Sounds right to me,
OK

I took half litre of wine
added 1 drop of solution, still had a little egg smell.
added a 2nd drop, wife could still smell egg.
added 3rd drop passed by the misses. no egg smell anymore.
Yeah!
I have now added 300 drops to 50 litre barrel, and hey presto cant smell the egg anymore.
Dosing level I think is 0.3ppm, which is legal, assuming my maths was correct.
 

Handy Andy

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Your numbers are off a little due to copper sulfate being only 25% copper by weight.
A 1% copper sulfate solution can be made adding 1g copper sulfate and topping up to 100ml with water.
A .1ppm copper addition would be approximately .15ml of the 1% solution added per gallon of wine.
A .5ppm copper addition would be approximately .75ml of the 1% solution added per gallon of wine.

Use the smallest dose needed to eliminate the odor. Bench trials are recommended to determine the required dose.
Seems my math was not correct, I did the above this morning before reading the replies.
So how much safety margin do I have ?
I work in metric units and assuming 1 US gallon = 4 litres

A 0.1ppm copper addition would be approximately .15ml of the 1% solution added per 4litres
A 0.1ppm copper addition would be approximately 0.04ml of the 1% solution added per litre

A 0.3ppm copper addition would be approximately 0.12ml of the 1% solution added per litre
A 0.3ppm copper addition would be approximately 6.0ml of the 1% solution added per 50litre

My solution was 1 gram in 1 litre so was 10 times weaker.

A 0.1ppm copper addition would be approximately 1.5ml of the 0.1% solution added per 4litres
A 0.1ppm copper addition would be approximately 0.4ml of the 0.1% solution added per litre

A 0.3ppm copper addition would be approximately 1.2ml of the 0.1% solution added per litre
A 0.3ppm copper addition would be approximately 60ml of the 0.1% solution added per 50litre

I added 300 drops equivalent to 15ml of 0.1% solution in 50 litres of wine.
Which is only 0.075ppm

Relief I dosed less than I thought, 25% of what I thought I had.
Thanks Stickman for the clarification.
 

Rice_Guy

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? Could you prevent the issue next year with Renaissance yeast ?
? could you prevent the problem with higher nutrient levels, and a little air ?

the Australian Wine Research Institute has several sessions on stinky sulphur, ex;
 

Handy Andy

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? Could you prevent the issue next year with Renaissance yeast ?
? could you prevent the problem with higher nutrient levels, and a little air ?
I suspect the problem was caused by me using too much K-meta on the must effectively stopping the fermentation getting started for a few days which may have resulted in the yeast being stressed.

Let us know how it smells next year please.
Will do, do you suspect the smell will come back ???
 

wood1954

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From my reading in the past using copper doesnt last. There is a product called reduless that is made from yeast that interacts with h2s and then is racked off , I used it once it worked great.
Reduless®, developed by Lallemand, is a unique inactivated yeast with biologically bound copper, developed to reduce sulfur compound off flavours. Reduless® reduces levels of hydrogen sulfide, diethyl sulfide, dimethyl sulfide, ,mercaptan and other sulfur related off-flavours in wine.Reduless® can enhance the overall quality
 
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