stupid chemicals question ?????

[fatbloke]

better still I have found it online
http://www.erbsloeh-geisenheim.de/en...nt/Kadifit.pdf

Yeah, found that anyhow, but the vigo site is a complete PITA - nice and pretty but badly laid out and organised as far as online shopping is concerned i.e. I could only find the Kadifit in the commercial section (the vigoltd.com site, rather than the home site vigopresses).

There doesn't seem to be any price list online either - how rubbish is that!

I mean, it's not as if it's a site that was designed/produced years ago, it's showing a 2009 copyright. So why they haven't got it sorted for full e-commerce I don't know.

Ah well, I'll just have to ring them so I've a full list of price numbers etc....


regards

jtfb

[grumpy]

Now I'm totally confused, is it 10 gtammes per litre or 100 grammes per litre for sodium Metabisulphite solution?

The wines at home video on Youtube states 50 grammes per gallon, by my amazing mathematical ability ( said modestly ) I calculate that to be 10 grammes per litre.

Honestly, I didn't use a calculator, or even pencil and paper to work that out. I'm thinking of applying for Mensa

[goldseal]

100 grammes per litre.

Do this by dissolving the powder in the water, then making it up to the required volume. Don't add 100g to 1 litre because you'll end up with more than 1 litre.

[lockwood1956]

Testing us all again Bob ??

Linky

So, surely the 10% solution would be 100 grammes in a litre of water Bob ???

regards

jtfb

indeed...

yet another typo/senior moment

[Rich]

So, surely the 10% solution would be 100 grammes in a litre of water Bob ???

regards

jtfb

Not quite a litre of water.. Start with your container with 100grams of sulphite in, then top up to the 1 litre mark with water, make sure it's mixed well. I keep mine in a 1 litre spray bottle for ease of use!

[SiSandrine]

Pot met sanitiser is is 5ml (spoon) of Citric 10 ml (spoon) in 5 litres. PS You can gas yourself with this (i know I have) it gives to a temp cough.

I was reading yesterday evening an old edition of Progressive Winemaking (1975) in which the messers Acton and Duncan stated that adding the citric acid shortens the lifespan of the sulphite solution by making it more unstable.

Is this believed true. I must admit that I have added citric acid previously and noticved the odour does go away more quickly whereas without citirc acid it lasts for several weeks.

Also I use 10% solution for sanitising and adding to must.

[koomber]

IAAC (I am a chemist) but not a very good one, and at any rate one who has been drinking stout

This is the reaction for sodium sulfite in water:
2HB (aq) + Na2S2O5 (aq) → 2 SO2 (g) + 2NaB (s) + H2O (l)

Where H is a proton
and B is the partner of the proton. (also called a base, hence the capital B)

In camden, it is not the Meta that is doing the killing bit, it is the SO2 (sulfur dioxide)

Water tends to (very slightly) form acid, even the absence of any ions (such as calcium or sodium). This will drive the reaction. Only thing is that water is only very VERY weakly acidic. Thus only a small amount of SO2 is generated. Bung in some acid (any acid) and you increase the number of protons up for grabs and generate more SO2.

As the SO2 is a gas, it is lost from the sulfite liquid, never to return (for all intents and purposes), thus:

acid = more SO2 = less Sulfite more quickly = sterilising solution borked.

wow. My chemistry knowledge came in useful!

[goldseal]

Yes, what ... .he said

[lockwood1956]

Adding citric acid makes the solution a little more effective, but does reduce the shelf life of solutions in storage.

[fatbloke]

Adding citric acid makes the solution a little more effective, but does reduce the shelf life of solutions in storage.

Ergo, just make a small batch (I usually make up a pint) to use to get your job done, then if there's any left over, just make up more for the next job etc etc.

So far, doing that hasn't caused me any problems at all......

regards

jtfb

p.s. and no, I haven't managed to gas myself - it can get a little "whiffy" when mixing it, but if it's done at arms length, it's not really an issue......

[SiSandrine]

I guess the thing is that advice to make up a batch that will keep for months in a container should be tempered with only if you make it without citric acid. Acton and Duncan also say that with a 10% solution citric acid is really not needed (in my 1975 edition).

[spritzer]

p.s. and no, I haven't managed to gas myself - it can get a little "whiffy" when mixing it, but if it's done at arms length, it's not really an issue......

That kinda depends how long your arms are

[Cellar_Rat]

That kinda depends how long your arms are

... and how big your spoons are LOL.